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Reactions of pentacyclo [7.6.1.0 2.8 0 3.5 0 10.15 ]hexadecatetraen-4-yl acetic acids ( 3a, b ), azatricyclo-[5.3.0 3.9 0 4.6 ]decaen-5-yl acetic acid ( 3c ), and its alcohol derivatives ( 12a, b ) with bromine gave bromocyclization products ( 10a, b, c ) and ( 13a, b ), respectively. The Curtius reaction of the car☐ylic acids ( 3a, b, c ) with diphenylphosphoryl azide gave the corresponding urethanes ( 19a, b, c ) together with compound 20 as a by-product. The cyclization reaction of 23 , which was easily prepared from reduction of the urethane ( 19a ) followed by chlorination with N-chlorosuccinimide, in refluxing methanol in the presence of silver nitrate gave mainly the parent amine compound ( 22 ) accompanied with a small amount of the cyclized product ( 24 ).

Conclusive evidence was obtained for the position of chiral alkyl groups in the esters of 3-nitrophthalic and 4-nitrohemimellitic acid, which are key substances demonstrating interesting chiroptical property due to twisting of the nitrobenzene chromophore controlled by the remote chiral groups through in phase twisting of the intervening substituents. Diphenylphosphorylazide (DPPA) was used as the reagent for modified Curtius rearrangement with good success. Since it acts specifically on carboxylic acid but not on ester function, only the former is converted to amine function. The amino compounds so derived were proved to be identical with the known substances. The method seems useful generally for determining the free carboxylic position in some partial esters of polycarboxylic acids.

2,3,5-Tri- O -benzyl- D -arabinofuranosyl bromide ( 4 ) was converted into 2,5-anhydro-3,4,6-tri- O -benzyl- D -glucononitrile ( 5 ), mixed with 20% of the D - manno epimer 6 . The mixture was reduced to the amine 7 , which via the N -nitrosoacetamide 10 afforded the 1-deoxy-l-diazo sugar 11 . Dipolar addition to dimethyl acetylene-dicarboxylate afforded the C -nucleoside derivative, dimethyl 3-(2,3,5-tri- O -benzyl-α-β- D -arabinofuranosyl)pyrazole-4,5-dicarboxylate ( 20 ). Selective ammonolysis afforded the 4-ester-5-carboxamide 21 , which was separated chromatographically into the α-(minor) and β-(major) anomers. Hydrazinolysis and Curtius reaction of the pair of 4-acid hydrazides (α- 22 and β- 22 ) afforded the anomeric 3-glycosyl-1 H -pyrazolo-[4,3- d ]pyrimidine-5,7-diones (α- 24 and β- 24 ). Hydrogenolytic debenzylation yielded the β- D )- arabino epimer ( 1 ) of oxoformycin B , and the α- D - arabino form 2 . These anomeric C -nucleosides were distinguished by circular dichroism spectra that showed the same relationship as α- and β- D - arabino anomers of normal purine nucleosides.

From 3-methyl-4-furoxancarboxylic acid hydrazide and 4-methyl-3-furoxancarboxylic acid hydrazide the corresponding azides have been synthesized. 3-Methyi-4-furoxancarboxylic acid azide normally underwent the Curtius reaction to give the expected carbamic acid derivative. The degradation of 4-methyl-3-furoxancarboxylic acid azide led to the N-(4-methylfuroxan-3-yl)-carbamic acid derivative at low temperatures and to N-(3-methylfuroxan-4-yl)carbamic acid derivative at higher temperatures.

Benznorcaradienycarbonyl azide (from naphthalene and methyl diazoacetate by known or unexceptional steps) decomposes on heating with benzyl alcohol in benzene to nitrogen and C 19 H 17 NO 2 (I). It is clear, from the fact that carbon dioxide is not evolved in the hydroxide-catalyzed cleavage to benzyl alcohol and C 12 H 11 NO 2 (II), that (I) is not a urethane, but a product of unexpected structure. By degradative and analytical methods and by independent synthesis, we have assigned the structure 2-benzyloxy-6:7-benzo-3-aza bicyclo [3.2.2] nona-6:8-diene-4-one to (I) (Chart 2). To our knowledge, no similar rearrangement during a Curtius reaction is recorded.

A simple, rapid and accurate micro-method for the analysis of mono- and diazide organic compounds is described. It is based on the Curtius rearrangement reaction. Glacial acetic acid is found to be the best decomposition medium. The acyl azide function yields two nitrogen atoms per azide group, but the diazides investigated ultimately give five nitrogen atoms per group on oxidation of their decomposition products, with acidified cerium(IV) sulphate solution. The decomposition time varies from 10 min for monoazides to 20 min for diazides. Accurate results were obtained for a representative series of 18 mono-and diazides.

Under mild alkaline conditions hemin can be catalytically hydrogenated to the iron complex of mesoporphyrin IX. Subsequent demetallation yields mesoporphyrin IX. In this way pure mesoporphyrin IX becomes readily accessible. In contrast, the mesoporphyrin produced from hemin by formic acid reduction has been shown by partition chromatography to be a mixture rather than a pure compound. Mesoporphyrin IX can be converted to pure etioporphyrin III in 20% yield by a seven-step reaction series including the Curtius rearrangement, Hofmann degradation, and catalytic hydrogenation.

It is possible to obtain a polyampholyte characterized by the presence of primary amine and carboxylic functions by a method based on the mutual reaction of functional groups along the polymeric chain. The great advantage of this method is the production of copolymers of a new type, from which the internal structure is well defined. In the present case the method is based upon interaction of an acyl chloride unit with a neighboring isocyanate function; these isocyanate functions have been introduced into the chains by two different methods, the Curtius reaction (sodium azide on polyacroyl chloride) and the Lossen reaction (hydroxylamine base on polyacroyl chloride). The solvents used were dioxane and dimethylformamide; the reactions were performed at ebullition. Higher boiling solvents yield an increasing amount of insoluble material. Both syntheses give end-products with the same properties. The structure of the polymers has been established from conductometric and potentiometric titration curves and also from nitrogen analysis. It was found that the interactions produce the formation of rings along the chain, and that these interactions are limited, as can be foreseen from statistical reasons; the residual groups remain free and become carboxylic functions after hydrolysis, or they react further and are transformed into amino functions. The final products are to be considered as copolymers of vinylamine and acrylic acid with a predominant alternate structure, and in which a given amount of amino groups have reacted with a neighboring acid function yielding lactam rings. However, these pyrrolidone units may be easily opened by alkaline hydrolysis, yielding thereby a polymeric chain with free amino and carboxylic functions, from which the proportions are approximately equivalent at high nitrogen content (12.5–13% N2). At lower nitrogen content the proportion of free carboxylic functions predominates; e.g., at 9.8% N2 there is an excess of 24% acidic functions. Determinations before and after hydrolysis allow the establishment of the internal structure of the copolymers; the proposed structure has been confirmed by benzoylation and deamination reaction and analysis of the benzoylated and deaminated copolymers.

Photolysis of cycloheptene-5-carbonyl azide, endo-norbornene-5-carbonyl azide and o-vinylbenzoyl azide gave very reactive acyl aziridines by internal addition of acyl nitrenes to the olefinic double bonds. Derivatives of 6-azabicyclo-[3,2,2]nonane and 1,2-dihydroisoindol-1-one were prepared. cis-2-Vinyl-cyclopropyl isocyanate, prepared photochemically at −78°, underwent Cope rearrangement at room temperature to 2,3-dihydro-1H-azepin-2-one. The mass spectra of a series of lactams are interpreted.

2-Methyl-3-ethoxycarbonyl-9, 10-dimethoxy-1, 2, 3, 4, 6, 7-hexahydro-11bH-benzo [a] quinolizinium salt was prepared by cyclization of the piperidone compound synthesized by the condensation of 3, 4-dimethoxyphenethyl bromide and 4-methyl-5-ethoxycarbonyl-2-piperidone in the presence of sodium hydride. Its amino derivative was prepared by the Curtius degradation, via the hydrazide, azide, and benzylurethan. The amino compound was diazotized with sodium nitrite in acetic acid and converted to the hydroxyl derivative, which was purified as its methiodide. In order to prove the presence of this hydroxyl group, the compound was led to its methanesulfonate. The hydroxy base was methylated with diazomethane, in the presence of fluoroboric acid in chloroform, and the objective methyl ether, i.e. rac-tetrahydrorotundine, was obtained as its methiodide. Some discussions were made on the reaction of aliphatic primary amines with nitrous acid.

Die epimeren 6-Athoxycarbonyl-bicyclo[3.2.2]nonene-(8) (1a und 2a) werden dargestellt; ihre Konfiguration wird zugeordnet durch Curtius-Abbau zu exo- bzw. endo-6-Aminobicyclo[3.2.2]nonen-(8) (1c und 2c) und durch die Synthesen von Bicyclo[3.2.2]nonen-(6) (4) bzw. Bicyclo[3.2.2]nonanon-(6) (6). Durch Reduktion von 6 und Aquilibrierung des Alkoholgemisches entstehen die exo/endo-isomeren Bicyclo[3.2.2]nonanole-(6) (7 und 8), deren Konfigurationen und Konformationen diskutiert werden. – Aus 4-[3-Athoxycarbonyl-2-oxocyclopentyl]-buttersaureathylester (13) wird uber das Dinitril 14d durch Zieglerschen Ringschlus Bicyclo[4.2.1]nonanon-(2) (11) erhalten. Die analoge Cyclisierung des cis-3-[3-Cyanmethyl-cyclopentyl]-propionitrils (17d) ergibt Bicyclo[4.2.1]nonanon-(3) (16), das auch bei der Desaminierung von 3-Aminomethyl-bicyclo[3.2.1]octanol-(3) (19) entsteht. Die Tiffeneau-Demjanow-Reaktion von 2-Aminomethyl-bicyclo[3.2.1]octanol-(2) (20) verlaft unter Bildung von 80% 11 und 17% 16, deren Wolff-Kishner-Reduktion zum Bicyclo[4.2.1]nonan (12) fuhrt. Syntheses in the Bicyclo[3,2,Z/nonane and Bicyclo[4,2, I] nonane Series The epimeric 6-ethoxycarbonyl-8-bicyclo[3,2,2]nonenes (1a and 2a) are prepared; their configurations are established from Curtius degradation giving exo-and endo-6-amino-8-bicyclo-[3,2,2]nonene (1c and 2c). Synthesis of 6-bicyclo[3,2,2]nonene (4) and 6-bicyclo[3,2,2]-nonanone (6) from the mixture of the epimers 1a and 2a is described. Reduction of 6 and equilibration of the obtained mixture of alcohols afford the exo/endo isomers of 6-bicyclo[3,2,2]nonanol (7 and 8). The configurations and conformations of these alcohols are discussed. – 2-Bicyclo[4,2,1]nonanone (11) is produced by Ziegler ring closure of the dinitrile 14d obtained from ethyl 4-(3-ethoxycarbonyl-2-oxocyclopentyl)butyrate (13). In the same way cyclization of cis-3-(3-cyanomethylcyclopentyl)propionitrile (17d) yields 3-bicyclo[4,2,1] nonanone (16). The latter is also obtained by deamination of 3-aminomethyl-3-bicyclo[3,2,1]octanol (19). The Tiffeneau-Demjanov reaction of 2-aminomethyl-2-bicyclo[3,2,1]octanol (20) gives 80% 11 and 17% 16, which on reduction by the Wolff-Kishner method yield bicyclo[4,2,1]nonane (12).

The use of sodium azide and organic acid azides for the control of potato root eelworm has been investigated: in suitable conditions they were effective both in greenhouse tests and in field trials. The biological activity of azides has been shown to arise from liberation of undissociated hydrazoic acid. The acid is only liberated in effective quantities in acid soils, but in such soils it is decomposed with formation of nitrogen. Organic acid azides are decomposed by a wide range of dust diluents and by soil, and there is some evidence that in diluents the main decomposition reaction is the formation of isocyanate by the Curtius rearrangement, whereas on wet soils extensive hydrolysis occurs giving hydrazoic acid, which is subsequently decomposed.

Jones and Mason claimed a number of years ago (1) that rearrangement of cis-olefinic acyl azides gave trans-olefinic isocyanates. However, several other workers have found that rearrangement of an acyl azide group attached to an optically active carbon gives configurationally identical products, a discovery which apparently conflicts with Jones and Mason's findings. We have reexamined the rearrangement of cis-crotonyl azide with stringent checks at each reaction step and found perfect retention of geometry in the product. Details of this finding are discussed.

Aminocyclopentadienylmanganese tricarbonyl, prepared by the Curtius degradation of azidoformylcyclopentadienylmanganese tricarbonyl as well as by hydrolysis or hydrogenolysis of the benzyl-oxycarbonyl derivative, has been found to be ten times less basic than aniline. The results of the Schmidt reaction carried out on several metallocenyl ketones indicate that the metal atom may play an important role in determining migratory aptitudes of the metallocenyl moiety in rearrangement reactions involving metallocenes.

Aus Acylmalonsaure-diathylestern 5 bzw. Acylcyanessigsaure-athylestern 9 werden uber die entsprechenden Chlorathylene 6 bzw. 10 2-Azido-athylen-l.l-dicarbonsaure-Derivate 7 bzw. 12 dargestellt. Von diesen liefern die Diathylester 7 bei der Thermolyse unter Stickstoff-abspaltung 5-Athoxy-isoxazol-carbonsaure-(4)-athylester 8. Da bei der Darstellung der 2-Azido-l-cyan-athylen-carbonsaure-(l)-athylester nur das Isomere mit zur Carbonester-funktion trans-standiger Azidogruppe entsteht, tritt hier bei der Thermolyse eine dem Curtius-Abbau analoge Umlagerung zu Keteniminen ein, deren Additionsprodukte z. B. mit Athanol isoliert werden. Activated Ethylenes, II. Synthesis and Thermolysis of 2-Azidoethylene-l, l-dicarboxylic Acid Derivatives Ethyl esters of acylmalonic acids 5 and acylcyanoacetic acids 9 are converted via the corresponding chloroethylenes 6 and 10 to derivatives of 2-azidoethylene-l.l-dicarboxylic acids (7 and 12). The diethyl esters of the latter 7 lose nitrogen on thermolysis and yield ethyl 5-ethoxy-isoxazole-4-carboxylates 8. The synthesis of the ethyl 2-azido-l-cyano-l-carboxylates produces only the isomers with the azido group trans to the ester group. Consequently their thermolysis leads to a rearrangement analogous to the Curtius degradation and produces ketenimines, the addition products of which are isolated.

1. A general method has been developed for the preparation in good yield on N-benzoylated imidazolidone derivatives by the Curtius reaction, which is applied to esters of N-benzoylated β-amino acids. 2. The reaction has been carried out with N-benzoyl-β-phenyl-β-alanine, N-benzoyl-β-(m-nitrophenyl)-β-alanine, and N-benzoyl-β-piperonyl-β-alanine. 3. It has been found that reaction of excess of hydrazine hydrate with N-benzoyl-β-(m-nitrophenyl)-β-alanine yields the hydrazide of β-(m-aminoplienyl)-N-benzoryl-β-alaniiie, i.e., reaction is accompanied by reduction of the Witro group.

In a mixed solvent of water-acetic acid-propionic acid, 3-phenanthrol was nitrated with an equimolar amount of nitric acid at - 25 - 20°C to obtain a mixture of mononitro compounds containing a small amount of polynitro compounds. The mixture consisted of 9-nitro-3-phenanthrol (2), 4-nitro-3-phenanthrol (3), and 2-nitro -3-phenanthrol (4), the amount of each product being decreased in this order. Further nitration of (3) and (4) in dilute acetic acid at 1112°C gave a common product, 4, 9-dinitro-3-phenanthrol (5). (5) was treated in glacial acetic acid with fuming nitric acid at 15°C to form 2 (?), 4, 9-trinitro-3-phenanthrol in a good yield. (3) is stable under acidic conditions in contrast to unstable 4-bromo-3-phenanthrols.Through reduction of the methyl ether of (4), the corresponding amine was obtained, as identified using an authentic sample of 3-methoxy-2-phenanthrylamine derived from 3-methoxy-2-phenanthrenecarboxylic acid by the Curtius reaction.

2 The2′-bisacylazide of 3,3′-bipyridine (1) has been synthesized from the (4,7)-phenantholine-5,6-dione (3) and the thermal decomposition of this new bisacylazide has been shown to give rise to the Curtius rearrangement and subsequent cyclization to the pyrido[2,3-h]-2,6-naph-thridinone ring system 8.

The introduction of an amino function on the bridgehead position of the bicyclo (3, 3, 1) nonane ring system has been smoothly achieved by the modified Curtius reaction on some bridgehead carboxylic acids. This method has been applied on 3β-methyl-9-ox-obicyclo (3, 3, 1) non-6-ene-1-carboxylic acid (XIV) to afford the unsaturated aminoketone (XVI) as its hydrobromide via the carbamate. XVI was transformed into the tricyclic lactam (XVIII), via the pyruvamide (XVII) followed by cyclization. XVIII was then reduced via its lactim-ether followed by oxidation to afford 2, 3, 5, 6, 7, 8-hexahydro-7β-methyl-3-oxo-1H-5, 8α-propenoquinoline (XXI) in good yield, which would provide useful intermediate for syntheses of the lycopodium alkaloids.

Die Synthese der Titelverbindungen erfolgte einmal durch Reduktion des Cyclopropancarbonsaureesters 1 zum Alkohol 4 und Einfuhrung der Stickstoff-Funktion durch eine Substitution an C-7 und zum anderen durch Curtius-Abbau des Cyclopropancarbonsaureazids 14. Wahrend das Aminoathyliden-Monosaccharid 10 in freiem Zustand erhalten werden konnte, war die Darstellung des freien Cyclopropylamins infolge seiner Zersetzlichkeit nicht moglich. Synthesis of 2.-3(2-Aminoethylidene)-2.3-dideoxy-D-mannose and Derivatives of 2.-3(Aminomethylene)-2.3-dideoxy-D-mannose — Amino Sugars with a Cyclopropane Ring The syntheses of the title compounds were realised first by reduction of the cyclopropane carboxylic acid ester 1 to the alcohol 4 and subsequent introduction of the nitrogen function via a displacement reaction at C-7 and second by a Curtius degradation of the cyclopropane carboxylic acid azide 14. The aminoethylidene monosaccharide 10 was obtained in free, protected form, however, preparation of the free cyclopropyl amine was not possible due to its instability.

4-Mono- and 4,4-disubstituted-3-imino-2-benzoyl-5-pyrazolones have been prepared from the corresponding ethyl mono- or disubstituted cyanoacetates and N-benzoylhydrazine. The presence of the imino group in 4,4-disubstituted-3-imino-2-benzoyl-5-pyrazolones was ascertained by the hydrolysis of 4,4-dibenzyl-3-imino-2-benzoyl-5-pyrazolone into 4,4-dibenzyl-3-oxo-2-benzoyl-5-pyrazolone. In order to prove that the benzoyl group in these pyrazolones was not in Position 1, the synthesis of 4-benzyl-3-amino-1-benzoyl-5-pyrazolone was attempted from 4-benzyl-3-carbethoxy-1-benzoyl-5-pyrazolone through a Curtius degradation of the 3-carbethoxy substituent into a 3-amino group. It was found that the 1-benzoyl group was hydrolyzed at the same time as the 3-carbethoxyamino substituent. The ultraviolet absorption spectra of all these compounds are reported and discussed briefly.

A simple one-step conversion of carboxylic acids to urethanes was achieved by diphenyl phosphorazidate (DPPA). The reaction procedure is quite simple, occurring by refluxing an equimolecular mixture of a carboxylic acid, DPPA, and triethylamine in the presence of a hydroxyl component. Aromatic, aliphatic, and heterocyclic carboxylic acids underwent rearrangements in satisfactory yields. As this modified Curtins reaction is much simpler and less laborious than the classical Curtius reaction and proceeds under mild conditions, it may have a broad synthetic utility.

The possibility of preparing 2-aminopyrazine 5-carboxylic acid and some of its derivatives by the Curtius reaction was investigated. The final step could be accomplished satisfactorily especially by hydrogenolysis or acid hydrolysis of the corresponding benzylurethanes.

In connection with our earlier studies on the orientation of phenanthrols, the nitration of 2-phenanthrol (1) was investigated. In dilute acetic acid, (1) was treated with an equimolar amount of 30% nitric acid at 03°C to obtain 1-nitro-2-phenanthrol (2) in 65.6 mol% yield and 3-nitro-2-phenanthrol (3) in 3. 2 mol% yield. Further nitration of (2) under more drastic conditions yielded almost quantitatively 1, 3-dinitro-2-phenanthrol (4), which was also obtained from (3) by a similar method. Upon addition of 65% nitric acid to the solution of (4) in conc. sulfuric acid at 05°C, 1, 3, x-trinitro-2-phenanthrol was formed. The methyl ether of (3) was reduced to give the corresponding amine, as identified with an authentic sample of 2-methoxy-3-phenanthrylamine derived from 2-methoxy-3-phenanthrenecarboxylic acid by the Curtius reaction.

From diethyl 3-t-butyladipate (5), via cis- and trans-4-t-butylcyclopentene-1,2-oxide (31, 32) as key compounds, the syntheses of cis-2-amino-cis-4-t-butylcyclopentanol (1), cis-2-amino-trans-4-t-butylcyclopentanol (2), trans-2-amino-cis-4-t-butylcyclopentanol (3) and trans-2-amino-trans-4-t-butylcyclopentanol (4) have been achieved. 1, 3 and 4 were also synthesized from the corresponding 2-hydroxy-4-t-butylcarboxylic acids by Curtius degradation of the hydrazides (11, 18, 19). The steric course of process leading to the above compounds is discussed.

Curtius degradation of 14α, 17α-etheno-16α-carboxypregn-5-ene-3β-ol-20-one acetate (IV) to the benzylurethane (V) is described. Selective catalytic reduction of 14α, 17α-etheno-16α-carbomethoxypregn-5-ene-3β-ol-20-one acetate (III) afforded 14α, 17α-ethano-16α-carbomethoxypregn-5-ene-3β-ol-20-one acetate (VI). Hunsdiecker degradation of the carboxylic acid VIII, derived from VI gave 14α, 17α-ethano-16α-iodopregn-5-ene-3β-ol-20-one acetate (IX). Hydrolysis of IX to the 3β-alcohol X was followed by catalytic reduction to 14α, 17α-ethano-5α-pregnane-3β-ol-20-one (XI). The latter compound was also prepared from 14α, 17α-ethenopregn-5-ene-3β-ol-20-one (XII). The stereochemistry previously assigned to I, on the basis of analogies, has been proved by a combination of chemical and physical evidence, including an x-ray crystal structure determination on IX.

1. The Curtius rearrangement in isomeric β- and γ-cycloheptatrienecarboxylic acids and norcaradlenecarboxylic acid was studied. It was shown that rearrangement goes without isomerization of the migrating hydrocarbon radical under the conditions employed. 2. The following were synthesized for the first time: 1,3,5-, 1,3,6- and 2,4,6-cycloheptatrienyl isocyanates, norcaradienyl isocyanates, 1,3,5-, 1,3,6- and 2,4,6-cycloheptatrienyl ureas, norcaradienyl urea, N-phenyl-N′-1,3,5-,-1,3,6-, and -2,4,6-cycloheptatrienyl ureas, and N-phenyl-N′-norcaradienyl urea. 3. The absorption spectra in the near ultraviolet (25,000–50,000 cm−1 of 22 derivatives of cycloheptatriene and norcaradeene were examined. It was shown that in nocaradiene derivatives (IV, R = COON, LOCI, CONH2, NCO) the three-membered ring transmits conjugation in a similar manner to a double bond.

In a synthetic approach to the veratrum alkaloids, experiments directed toward the conversion of deoxycholic acid (I) to a 5 α -C-nor-D-homo-dinorcholan-22-oic acid (III) are described. Reaction of the diacetate of I with lead tetraacetate, gave 3 α, 12 α -diacetoxy-24-nor-5 β -chol-22-ene (VIII), which on periodate-permanganate oxidation afforded diactoxybisnordeoxycholic acid (IX). The olefin (VIII) was also obtained from I by a Curtius reaction, followed by methylation and Hofmann elimination. The stereochemistry at C-5 in this series was inverted by treating 3-oxo-12 α -acetoxy-23,24-dinor-5 β -cholan-22-oic acid (XI) with bromine, followed by dehydrohalogenation, metal ammonia reduction and sodium borohydride reduction to give the 5 α -isomer (XIII) of bisnordeoxycholic acid. The tosylhydrazones of the 12-ketones derived from XII and XIII were subjected to the Bamford-Stevens reaction and both compounds gave complex mixtures of olefins. A product from the reaction of XIII was a C-nor-D-homo lactone, (XV), which was characterized by principally spectroscopic methods.

Chrysanthemyl isocyanate (4, cis: trans = 5 5 ) was prepared from chrysanthemic acid (1, cis: trans = 4 6 ) via the corresponding acid chloride (2) and acid aride (3). In these successive reactions, any appreciable change of the isomer ratio was not observed, indicating that the Curtius rearrangement proceeds through a concerted process. Chrysanthernoyl-isocyanate (6) and -isothiocyanate (7) were prepared from 2 and some reactions of these isocyanates, (4, 6, and 7) were carried out to obtain chrysanthemyl and chrysanthemoyl urea and urethane derivatives (8a-j, 9a, b, and 10a, b), imidazotrione derivatives (11a, b) and a thiadiazole derivative (12). The reaction of chrysanthemamide (5a, b) with oxalyl chloride to give a spiro oxazolidine-4,5-dione (17a, b) was investigated and its mechanism proposed.

The Curtius reaction was studied on the example of the azides of the 2,6-adamantanedione-1,7-di-carboxylic, 2,6-adamantanedione-1,3,5,7-tetracarboxylic and 1-bromo-3-adamantaneearboxylic acids.

The preparation of cis-3,4-ureylenethiophane (23) was attempted through three different routes. cis-3-Carbomethoxyamino-4-carbomethoxythiophane (20A), which had been obtained by the Lossen rearrangement of N-phenylsulfonyloxythiophane-cis-3, 4-dicarboximide (19), was selectively hydrolyzed to cis-3-carbomethoxyamino-4-carboxythiophane (21A), the modified Curtius rearrangement of which gave N-carbomethoxy-cis-3, 4-ureylenethiophane (22A). The alkaline hydrolysis of 22A afforded 23. However, an attempt to prepare 23 through two sulfone derivatives, (6) and (14), was unsuccessful.

We wish to report a modification of the Curtius Degradation which facilely affords high yields of isocyanates from acid chlorides or anhydrides under “single-pot” conditions. Trimethylsilyl acide attacks the reactive carbonyl groups of cyclic anhydrides and isomaleimides according to Eqn. 1, giving formally a Curtius Degradation product.

Three Convenient syntheses of cis-1, 2-ureylenecyclopentane (VI) and cis-cis-3-methyl- 1, 2-ureylenecyclopentane (VIa), from 2-carbethoxycyclopentanone (I) and 5-methyl-2-carbethoxycyclopentanone (Ia) respectively, are described. The Curtius degradation of cis-2-aminocyclopentanecarboxylic acid derivatives took place without cis-trans isomerization. The hydrogenation of ethyl 3-methyl-2-ureidocyclopent-1-ene-1-carboxylate at 70°C gave two isomeric products, the major (IIIa), cis-cis-, and the minor (IIIb), cis-trans-3-methyl-2-ureido-1-carbethoxycyclopentane.

1. It has been established that by the decarboxylation of the glycidic acid , obtained by Darzens' method from cis-decahydro-2-naphthol of m.p. 105°, a mixture of stereoisomeric decahydro-2-naphthaldehydes is formed; these have not been investigated further. 2. The synthesis has been affected, by Rodionov's method, of β-(2-decalyl)-β-alanine (β-aminodecahydro-2-naphthalenepropionic acid), which also appeared to be a mixture of isomers, the separation of which was not carried out. 3. By taking advantage of the different ether-solubilities of the acid chlorides of the N-benzoylated β-(2-decalyl)-β-alanines, the corresponding amides, m.p. 210–212° and 250–252°, were isolated. 4. The two amides were converted by careful hydrolysis into the isomeric N-benzoylated β-(2-decalyl)-β-alanines. 5. It has been shown that when the amide of N-benzoyl-β-(2-decalyl)-β-alanine is heated with acetic anhydride, a transacylation reaction occurs, and instead of 6-(2-decalyl)-6,6-dihydro-2-phenyl-4(3H)-pyrimidinone the corresponding 2-methyl derivative is obtained. 6. In order to characterize β-(2-decaclyl)-β-alanine, the corresponding ureido acid and 6-(2-decalyl)-hydrouracil were prepared. 7. Esters and hydrazides of N-benzoyl-β-(2-decalyl)-β-alanine have been prepared, and, by means of the Curtius reaction, they have been converted into 3-benzoyl-4-(2-decalyl)-2-imidazolidones and the corresponding 4-(2-decalyl)-2-imidazolidinone.

In contrast to the thermal decomposition which produces 1-phenylindazolone in 90% yield, the photolysis of diphenylcarbamoyl azide in alcohols (and other solvents) gives 1-phenylbenzimidazolone, diphenylamine and the corresponding carbazates (except in t-amyl alcohol where no carbazate is formed), In no case could 1-phenylindazolone be isolated. The formation of 1-phenylbenzimidazolone is shown to proceed via the singlet diphenylcarbamoyl nitrene while the generation of diphenylamine is believed to occur by radical abstraction of the triplet nitrene. The carbazates arise by the Curtius rearrangement of the H bonded azide.

The decomposition of organic carbonylazides can lead to the formation of nitrenes. Ethoxycarbonylnitrene is formed in the photolytic and thermal decomposition of ethyl azidoformate and by α-elimination from N-(p-nitrobenzenesulfonyloxy)urethan. Both of the possible electronic states of this nitrene take part in intermolecular reactions. Pure singlet nitrene is formed by α-elimination from the urethan and on thermal decomposition of ethyl azidoformate, but changes so rapidly into the triplet form that the reactions of both forms are observed. Singlet ethoxycarbonylnitrene undergoes selective and stereospecific insertion into CH bonds and adds stereospecifically to olefins. Triplet ethoxycarbonylnitrene, however, does not undergo insertion into CH bonds, and adds to olefins with complete loss of the geometric configuration. By following quantitatively the stereospecificity of the addition reaction and by selective interception of the triplet and singlet forms of the nitrene, it can be shown that the photolysis of ethyl azidoformate leads directly to nitrene of which one third is in the triplet state. In the decomposition of aryl- and alkylcarbonylazides (acid azides), the removal of nitrogen is accompanied by a synchronous rearrangement to isocyanates (Curtius rearrangement). In this system, nitrenes are obtained only by photolysis. They add to double bonds and undergo very selective insertion into CH bonds, but do not rearrange at a measurable rate to isocyanates. The photolytic Curtius rearrangement is also a concerted reaction.

A new synthetic route for N, N-dimethyl-1-m-hydroxyphenylcyclohexaneethylamine (IX) from ethyl cyclohexylidenecyanoacetate is described. 1-(m-Methoxyphenylcyclohexyl) trimethylamine (XII) was prepared by the Curtius degradation of 1-m-methoxyphenyl-cyclohexaneacetic acid (V) and subsequent dimethylation.

Chemical properties of l-azaazulan-2-one (I) and its 3-substituted derivatives such as 3-acetyl, 3-cycloheptatrienyl and 3-ethoxycarbonyl were investigated. It was shown that the electrophilic substitution reactions take place at the 3-position, replacement of the substituents occuring in some cases by the reactions with cationoid reagents. The Beckmann rearrangement, Curtius rearrangement, Hofmann degradation reaction, Stevens-McFadyen reaction, etc. of these compounds are described.

A modified Curtius reaction of N-benzyloxycarbonyl-L-proline (I) with diphenyl phosphorazidate (DPPA) in the presence of triethylamine in tert-butyl alcohol afforded the allophanate (III) as the major product but the expected carbamate (II) as a minor product. Similar result was obtained in the case of the ordinary Curtius reaction of I. However, the use of tert-butyl carbamate (X) as an additive changed the reaction course and the desired carbamate (II), though accompanied by racemization, was obtained in good yield.