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The sequentially repeating nature of the core mucin polypeptide chain MUC-1 on the surface of malignant cells makes it an excellent target for cancer immunotherapy. We describe a reliable and efficient method of synthesizing oligomers, up to five tandem repeats and oligomer heterotope derivatives with a 15-amino acid epitope from tetanus toxin using an improved convergent solid-phase peptide synthesis. The different oligomers were easily distinguishable by reverse-phase high pressure liquid chromatography, but they were poorly fixed and migrated with the same migration rate, irrespective of size, in electrophoretic studies. In contrast, the oligomer heterotopes exhibited size-dependent electrophoretic behavior but in high pressure liquid chromatography chromatograms the different heterotopes were eluted simultaneously in two peaks representing the L- and D-enantiomers of the derivatives. The oligomer heterotopes were recognized as antigens in Western blotting with a murine monoclonal antibody against the epitope APDTR. In enzyme immunoassay studies with the same antibody an increasing reactivity was observed against the larger oligomers and confirmed by inhibition assays as the MUC-1 pentamer was the most efficient inhibitor. These results support the suggestion that the pentamer attains a structure closer to the native conformation and is more immunogenic. In conclusion, large composite peptides can be reliably synthesized with the convergent solid-phase peptide strategy offering an attractive option to vaccine designing and development.

Model peptides containing the nucleophilic amino acids Trp and Met have been synthesized with the application of Fmoc/Trt- and Fmoc/tBu-amino acids, for comparison. The deprotection of the peptides synthesized using Fmoc/Trt-amino acids in all cases leads to crude peptides of higher purity than that of the same peptides synthesized using Fmoc/tBu-amino acids. © Munksgaard 1998.

Cyclic amide-linked angiotension II (ANGII) analogues have been synthesized by novel strategies, in an attempt to test the ring clustering and the charge relay bioactive conformation recently suggested. These analogues were synthesized by connecting side chain amino and carboxyl groups at positions 1 and 8, 2 and 8, 3 and 8, and 3 and 5, N-terminal amino and C-terminal carboxyl groups at positions 1 and 8, 2 and 8, and 4 and 8, and side chain amino to C-terminal carboxyl group at positions 1 and 8. All these analogues were biologically inactive, except for cyclic [Sar1, Asp3, Lys5]ANGII (analogue 10) which had high contractile activity in the rat uterus assay (30% of ANGII) and [Lys1, Tyr(Me)4, Glu8]ANGII (analogue 7) which had weak antagonist activity (PA2 approximately 6). Precyclic linear peptides synthesized using 2-chlorotrityl chloride resin and N alpha-Fmoc-amino acids with suitable side chain protection were obtained in high yield and purity and were readily cyclized with benzotriazol-1-yloxytris(dimethylamino)-phosphonium hexafluorophosphate as coupling reagent. Molecular modeling suggests that the ring structure of the potent analogue can be accommodated in the charge relay conformation proposed for ANGII.

The disulphide bridge-containing protected peptides calcitonin (1-10) and (Tyr1)-somatostatin-14 were obtained in good yields and high purity by simultaneous iodine oxidation of Cys (Trt) residues and release of the protected peptides from 2-chlorotrityl resin.

The esterification of 2-chlorotrityl chloride resin with Fmoc-amino acids in the presence of DIEA is studied under various conditions. High esterification yields are obtained using 0.6 equiv. Fmoc-amino acid/mmol resin in DCM or DCE, in 25 min, at room temperature. The reaction proceeds without by product formation even in the case of Fmoc-Asn and Fmoc-Gln. The quantitative and easy cleavage of amino acids and peptides from 2-chlorotrityl resin, by using AcOH/TFE/DCM mixtures, is accomplished within 15-60 min at room temperature, while t-butyl type protecting groups remain unaffected. Under these exceptionally mild conditions 2-chlorotrityl cations generated during the cleavage of amino acids and peptides from resin do not attack the nucleophilic side chains of Trp, Met, and Tyr.

Tyr0-Atriopeptin II was synthesized on a 2-chlorotrityl resin by both the stepwise and the convergent approach. For both methods an Fmoc/tBu(Trt)-based protection scheme was used. The convergent methodology utilizes the sequential condensation of four protected peptide fragments. These were chosen so that after every condensation reaction, the amino-terminal region of the newly formed resin-bound peptide did not contain a β-turn. This ‘designed’ convergent synthesis gave the target peptide in much higher yield and purity than the conventional step-by-step synthesis.

A mixture of hexafluoroisopropanol–dichloromethane (1:4 v/v) acts as a fast, effective and convenient reagent for cleaving protected peptide fragments with a minimal amount of racemization from 2-chlorotrityl chloride resin.

(Silylamino)borane sind weitgehend inert gegenuber einer Umsilylierung bzw. BN-Spaltung durch Chlormethylsilane. Hingegen erhalt man B- und/oder Si-halogenierte (Silylamino)borane aus Si-halogenierten Disilazanen und Borhalogeniden oder besonders einfach aus Nonamethylcyclotrisilazan 14 und Borhalogeniden. Verschiedene Zwischenprodukte, die bei der Reaktion von 14 und (CH3)2BBr gebildet werden, geben Hinweise auf den Abbau dieses Ringsystems. Contributions to the Chemistry of Boron, LXXXVII. B,Si-Functional (Silylamino)boranes: a Contribution to the SiN-Cleavage by Boron Halides (Silylamino)boranes are virtually inert towards transsilylation or BN-cleavage by chloromethylsilanes. However, B- and/or Si-halogenated (silylamino)boranes are easily obtained from Si-halogenated disilazanes and boron halides, and, especially, from nonamethylcyclotrisilazane 14 and boron halides. Information concerning the degradation of this ring system have been obtained from several intermediates formed in the reaction of 14 with (CH3)2BBr.

Die Phenol-Funktion von Tyrosin-Derivaten last sich mit Alkoholen unter milden und neutralen Bedingungen mit Hilfe des Redox-Systems Triphenylphosphan/Diethyl-azodicarboxylat als Kondensationsmittel alkylieren. Redox Alkylation of Tyrosine Derivatives Tyrosine derivatives are alkylated at the phenolic function with alcohols under mild and neutral conditions by using the redox condensation system triphenylphosphane/diethyl azodicarboxylate.

Trt- und Fmoc-Aminosauren werden durch Triphenylphosphan (TPP) und Diethyl-azodicarboxylat (DEAD) mit p-Alkoxybenzylalkohol-Harz (ABAR, 1) und mit Diphenylmethanol-Harz (DPMR, 2) bei 0°C in Tetrahydrofuran verknupft. Die resultierenden Harze werden zur Peptidsynthese nach der „Solid-phase”-Strategie mit N-Tritylaminosaure-(1-benzotriazolylestern) 9 eingesetzt. Anchoring of Amino Acids on Hydroxy Group-Containing Resins and Their Application to Peptide Synthesis Using N-Tritylamino Acid 1-Benzotriazolyl Esters Trt- and Fmoc-amino acids has been attached to p-alkoxybenzyl alcohol resin (ABAR, 1) and diphenylmethanol resin (DPMR, 2) using triphenylphosphan (TPP) and diethyl azodicarboxylate (DEAD) at 0°C in tetrahydrofuran. The derived resins have been applied in “solid-phase” peptide synthesis using N-tritylamino acid 1-benzotriazolyl esters 9.

35)Cl-chemische Verschiebungen (δ35Cl) von 17 Alkylchloriden und 4 Alkenylchloriden werden mitgeteilt. Eine lineare Korrelation zwischen δ35Cl und δ19F analoger Fluoride fur Alkylhalogenide des Typs CnH2n+1 X und CnH2nX2 zeigt den gleichsinnigen Einflus des Alkylrestes auf die chemischen Verschiebungen δ35Cl und δ19 F. Bei mehr als zwei Halogenatomen pro Kohlenstoff versagt diese Beziehung, ebenso bei Alkenylhalogeniden; Grunde hierfur werden diskutiert. Zwischen der berechneten Ladungsdichte am Chlor und δ35Cl last sich keine lineare Korrelation herstellen. 35Cl NMR Studies on Alkyl and Alkenyl Chlorides 35Cl chemical shifts (δ35Cl) are reported for 17 alkyl chlorides and 4 alkenyl chlorides. A linear correlation results between δ35Cl and δ19F of analogous compounds of the type CnH2n+1 X and CnH2nX2. This relationship is not valid if there are more than two halogen atoms bonded to one carbon atom and also in the case of alkenyl halides. The reasons for this are discussed. There is no linear correlation between the calculated charge density on chlorine and δ35Cl.

The synthesis of permethylated silaborazines starting from Br(CH3)B-NCH3-Si(CH3)2Br or Br(CH3)B-NSi(CH3)3-Si(CH3)2Br is described. These may in turn be used to prepare phosphaborazines, since phosphorus halides replace selectively the sila group from the silaborazines. The P-Cl bond of P-chloro-pentamethylphosphaborazine is more reactive than the P -N and B-N bonds of the ring and allows selective nucleophilic substitution reactions at phosphorus. The NMR data of the new compounds suggest a nonplanar ring configuration.

The disodium salts of N-trityl-hydroxyamino acids 2 prepared in situ with NaH, in the presence of imidazole, were selectively alkylated with alkyl iodides to give N-trityl-O-alkyl-hydroxyamino acids 3 . Compounds 3 were readily converted to O-alkyl-hydroxyamino acids 5 or other intermediates useful for incorporation into a peptide chain. The applicability of these derivatives in the preparation of related peptides is illustrated by the synthesis of the protected analogues of enkephalin N-carbobenzoxy-tyrosyl-glycyl-glycyl-phenylalanyl-(O-ethyl) serine benzyl ester and N-carbobenzoxy-tyrosyl-glycyl-glycyl-phenylalanyl-(O-methyl) homoserine benzyl ester.

N-Tritylaminosaure-(1-benzotriazolylester) 1 werden bei 30–80°C in Gegenwart von uberschussigem Triethylamin racemisierungsfrei an Amino-Komponenten gekuppelt. Peptide Synthesis at Elevated Temperature Free of Racemisation N-Tritylamino acid 1-benzotriazolyl esters resist racemisation during coupling with amino components at 30–80°C in the presence of excess triethylamine.

Preparation of Tritylamino Alcohols N-Tritylamino acid trimethylsilyl esters 2 were mildly reduced with LiAlH4 to give N-tritylamino alcohols 3 in high yields and purity. Other methods provided 3 in lower yields.

Die substituierten Diphenylmethyl-Harze 5b–e und das α-Methylbenzyl-Harz 6 wurden hergestellt und nach der Methode von Mitsunobu mit Trt- und Fmoc-Aminosauren verestert. Nach wachsender Stabilitat ihrer Esterverknupfung mit Aminosauren gegenuber Trifluoressigsaure kann man die untersuchten Harze wie folgt einordnen: 6 ≤ 5b

14N chemical shifts of a series of cyclic and noncyclic aminophosphines are reported. The nuclear shielding of nitrogen decreases with increasing number of halogen substituents at phosphorus as well as with increasing number of phosphinyl groups attached to nitrogen. In addition to the influence of electronegativity PN(π)-interactions may account for the observed shielding. Steric effects are discussed.

14N chemical shifts for compounds of types Download : Download full-size image are reported as well as a collection of 14N NMR data of selected alkyl-, stannyl-, germyl-, and plumbylamines for comparison. The strong +I effect of the trimethylsilyl group is shown by δ(14N) when X acts as an inductive electron-withdrawing substituent. If mesomeric effects of X must be considered, δ(14N) indicates participation of the free electron pair at nitrogen attached to silicon in π bonding or in an extension of the π-electron system. Silicon-nitrogen(dp) π bonding accounts, at least partly, for the δ(14N) value of N-trimethylsilylpyrrol.

Die thermische Stabilitat von Diborylaminen wird durch die sterisch anspruchsvolle Trimethylsilygruppe am zentralen N-Atom betrachtlich erhoht. Ausgehend von N[Si(CH)3]3 and CH3 BBr2 ist das Diborylamin (CH3)3Si- N(BBrCH3)2 zuganglich, dessen Br-Atome sich teilweise oder vollig gegen (CH3)2N-, CH3O- oder CH3S-Gruppen austauschen lassen. Alle diese Diborylborlamine mit funktionellen Gruppen am Bor sind mindestens bis 150°C stabil. Die BBr3 - Umsetzung von (CH3) and schlieslich Br(CH)Si-N (BB4CH3)2. Struktur and Bindungsverhaltnisse der neuen Diborylamine werden an Hand der NMR-Daten besprochen. Contributions to the Chemistry of Boron, LXVIII. - Diborylamines with Functional Groups Attached to Born Tge thermal stability of diborylamines is considerably increased by the bulky trimethylsily1 group attached to the central N-atom.The diborylamine (CH3)3Si -N (BBrCH3)2 is obtained from N [Si(CH3)3] and CH3BBr2 and its Br atoms can be partly or fully exchanged for (CH3)2 N CH3O, or CH3S groups. All these diborylamines are stable to at least 150°C.The reaction of BBr3 with (CH3)2N-BCH3-NSi(CH)Si - N Structure and Bonding in the new diborylamines are discussed on the basis of their NMR data.

N.m.r. parameters (1H, 11B, 13C, and 31P) of a triazaphosphadiborine and a triazaphosphaborolidine and their corresponding ‘phosphinylium’ cations have been measured. The geminal 31P–13C coupling constants are consistent with non-planarity of the ring systems, this non-planarity being greater in the neutral than in the cationic species. Values of 3J(31PNCH) are less sensitive to changes in ring conformation and therefore must be used with care to assess this unless independent evidence is available.

1. 1. The amino acid analogs O -allyl-tyrosine, O -allyl-threonine, O -allyl-serine and O -allyl-homoserine, have been synthesized and their effect on protein synthesis and secretion in cultured C. capitata fat body and salivary glands have been studied. 2. 2. The analogs had an inhibitory effect on protein synthesis in both tissues. Moreover, the analogs caused a slight increase in protein secretion in the fat body in comparison to the control. 3. 3. The intracellular transit time of protein secretion in treated and non-treated fat body was found essentially the same (about 10 min).

Es werden einfache Methoden zur Darstellung von Ditrityl-Aminosauren 3 und ihre Anwendung zur Synthese der Peptide 9–27 beschrieben. Selektive Nα-Detritylierung wird bei 3 und bei den synthetisierten Ditrityl-Peptiden durch Einwirkung von 1proz. Trifluoressigsaure in Dichlormethan erzielt. Die an der Seitenkette detritylierten Aminosauren 5 lassen sich unter Schotten-Baumann-Bedingungen durch Reaktion mit Fluorenylmethylchlorformat in die entsprechenden Fluorenylmethoxycarbonyl-Aminosauren 6 uberfuhren. Application of the Trt and Fmoc Groups for the Protection of Polyfunctional α-Amino Acids Simple methods for the preparation of ditrityl amino acids 3 and their application for the synthesis of the peptides 9–27 are described. Selective detritylation of 3 and of the synthesized ditrityl peptides is achieved with 1% trifluoroacetic acid in dichloromethane. The resulting Nα-detritylated amino acids 5 were converted into the corresponding fluorenylmethoxycarbonyl amino acids 6 under Schotten-Baumann conditions using fluorenylmethyl chloroformate.

A series of bis(boryl)hydrazines X(CH3)B-CH3N-NCH3-B(CH3)X (X = F, Cl, Br, SCH3, N(CH3)2, CH3) has been prepared by various methods and investigated by NMR, MS and PE Spectroscopy. The new oxidative ring opening of 2, 3, 4, 5-tetramethyl-1-thia- 3,4-diaza-2,5-diborolidine by bromine to yield Br(CH3)B-CH3N-NCH3-B(CH3)Br and sulfur yields the syn/syn conformer which rapidly adopts also the syn/anti and the thermodynamically favoured anti/anti conformation. All bis(boryl)hydrazines possess planar geometry at the nitrogen atom as suggested by the 14N NMR data and adopt gauche conformation as indicated by their He(I)-photoelectron spectra.

Zusammenfassung The esterification of several partially protected peptide fragments through the C-terminal or a free side chain carboxy group with hydroxy groups containing resins and the 2-chlorotritylchloride resin 8 is described. As an application example crude protected Leu15 - gastrin I ( 15a ) has been obtained in 99% yield by the “solid-phase” method using 8 as the solid support. Crude 15a has been deprotected to free Leu15 - gastrin ( 16 ) which is thus obtained in 92% yield and 90% purity.

N-Tritylmethionin-Derivate liefern durch Uberfuhrung in Methylsulfonium-Salze und anschliesende Einwirkung von Natriumhydrid oder Kalium-tert-butylat die Heterocyclen N-(Trityl-L-homoserinlacton (3), (S)- bzw. (R)-3-(N-Tritylamino)tetrahydrofuran (7a, 7b), (S)-1-Hydroxy-3-(N-tritylamino)-2-pyrrolidinon (14), (S)-4-(N-Tritylamino)-1,2-oxazinan-3-on (15), (S)-3-(N-Tritylamino)-2-pyrrolidon (23), (S)-1-tert-Butyloxycarbonylamino-3-(N-tritylamino)-2-pyrrolidon (27) und (S)-2-Methyl-4-(N-tritylamino)-1,2-oxazinan-3-on (18). Durch Methylierung von 14 und 15 erhalt man (S)-1-Methoxy-3-(N-tritylamino)-2-pyrrolidon (17) bzw. 18. Die Stereochemie der Verbindungen 3, 7a und 17 wird durch Rontgenstrukturanalyse ermittelt. Application of N-Tritylmethionine in the Preparation of Heterocycles of Biological and Synthetic Interest Treatment of the methylsulfonium salts of the corresponding N-tritylmethionine derivatives with sodium hydride or potassium tert-butoxide provides the heterocycles N-trityl-L-homoserine lactone (3), (S)- and (R)-3-(N-tritylamino)tetrahydrofuran (7a, 7b), (S)-1-hydroxy-3-(N-tritylamino)-2-pyrrolidinone (14), (S)-4-(N-tritylamino)-1,2-oxazinan-3-one (15), (S)-3-(N-tritylamino)-2-pyrrolidone (23), (S)-1-tert-butyloxycarbonylamino-3-(N-tritylamino)-1,2-oxazinan-3-one (18). Methylation of 14 and 15 yields (S)-1-methoxy-3-(N-tritylamino)-2-pyrrolidone (17) and 18, respectively. The stereochemistry of compounds 3, 7a, and 17 has been determined by X-ray crystal structure analysis.

(S)-4-(tert-Butyloxycarbonylaminooxy)-2-(tritylamino)buttersaure (8) und das p-Toluolsulfonat von (S)-2-Amino-4-(phthalimidooxy)buttersaure-phenacylester (10) werden in funf bzw. drei Stufen aus N-Tritylhomoserin (2) synthetisiert. L-Canaline Derivatives of Interest in Peptide Synthesis (S)-4-(tert-Butyloxycarbonylaminooxy)-2-(tritylamino)butyric acid (8) and the p-toluenesulfonate of phenacyl (S)-2-amino-4-(phthalimidooxy)butyrate (10) have been synthesized from N-tritylhomoserine (2) in five and three steps, respectively.

L-Homoserine was tritylated via its silylated product with Me2SiCl2 or Ph2SiCl2 in 65-68% yield. Also N-Trt-L-methionine upon treatment with Mel and degradation of the resulting sulfonium salt with KOH yielded N-Trt-L-homoserine in 75% yield. Both routes provided N-Trityl-L-homoserine with identical physical data. In contrast to N-alkyloxycarbonyl-L-homoserine derivatives, N-Trt-L-homoserine shows no tendency to spontaneous lactonization.

Application of 4-Polystyryltriphenylmethyl Chloride to the Syntheses of Peptides and Amino Acid Derivatives Use of polymer-bound trityl chloride as an α-amino protecting group of amino acids allows simple and high-yield syntheses of amino acid derivatives and peptides.

P-perhalogenated cyclotri(λ3 -phosphazanes) 3 a, b are obtained from the reaction of 1 or 2 with excess PX3 (X = Cl, Br). Under mild reaction conditions 4-7 are found to be intermediates. The existence of a six-membered ring trimer is proven by NMR and mass spectroscopy. No dimer (XPNMe)2 could be detected.

A Novel Preparation of Amino Acid Diphenylmethyl Esters and Their Application in Peptide Synthesis Trityl amino acid diphenylmethyl esters 2 were prepared by Mitsunobu condensation of tritylamino acids 1 with diphenylmethanol using excess triphenylphosphane and diethyl azodicarboxylate. The esters 2 were converted into the corresponding p-toluenesulfonates 3 on treatment with p-toluenesulfonic acid. The removal of the N-trityl group in the presence of the diphenylmethyl ester group is studied by the preparation of leucineenkephalin (12). Best selectivity is obtained when 1-hydroxybenzotriazole in trifluoroethanol is used as detritylation reagent.

Simple methods for the preparation of the ditrityl amino acids (III) (from (I)), (IV) (similarly obtained), (VIII) (from (Va)), or (X) (from (Vb) via (IX)) are described.

γ-Methyl (S)-glutamate (I) is protected to give the tritylamino derivative (III) which is transformed into the aminohydroxypentanoic acids (V) and (IX) mentioned in the title.