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A novel one-pot, two-step preparation of 5-aryltetrazoles from aromatic aldehydes and alkylhydrazines is presented.

3-Substituted (Z)-4-hydroxybut-2-en-1-yl acylates were regioselectively obtained in 2–98% yields by acylations of the corresponding 2-substituted (Z)-but-2-ene-1,4-diols with 10 equiv of vinyl acyl...

The synthesis of crystals of a zinc- and tin-based earth-abundant element nitride (ZnSnN2) semiconductor was successfully achieved via a metathesis reaction under high pressure. Pressures exceeding 5.5 GPa were required to obtain single-phase crystals. The material's bandgap was determined to be 1.4 eV, which is ideal for photovoltaic absorbers and visible light-active photocatalysts. The decomposition temperature of the material was estimated to be approximately 350‒400 °C at atmospheric pressure. Finally, the chemical stability of the material against alkali and acid solutions was sufficient for photovoltaic and photocatalytic applications.

Allylic alcohols reacted with Et 2 Zn and CH 2 I 2 in the presence of a catalytic amount of fluorous disulfonamide 3a to afford the corresponding cyclopropylmethanols in 69%-quantitative yields with 49–85% ee. Recovery of the fluorous ligand 3a was readily performed from the reaction mixture by the fluorous solid-phase extraction (FSPE), and the recovered 3a could be reused without a significant loss of the catalytic activity and enantioselectivity.

The reaction tolerates variously substituted arylmethyl ketones as well as hetarylmethyl ketones and is performed using alkyl nitriles, benzonitrile as well as succinonitrile as the reaction partner.

The formal synthesis of jiadifenin, which has potent neurotrophic activity, was accomplished using intramolecular Mizoroki–Heck reaction and tandem Tsuji–Trost cyclization/lactonization reaction as key steps. Intramolecular Mizoroki–Heck reaction was employed for the construction of the A ring moiety accompanied with the formation of C9 quaternary center, which was dramatically promoted by protic solvent. Tandem Tsuji–Trost cyclization/lactonization reaction was applied to the successive cyclization of the BC ring system to elaborate under conditions, Pd(OAc)2, (±)-BINAP, and LiOAc in t-BuOH, leading to Theodorakis's intermediate followed by a few functionalizations.

The novel fluorous organocatalyst, which can be easily prepared from the inexpensive and commercially available L-tyrosine, is effectively employed in the title reaction under mild conditions.

Best results are achieved performing the reaction in the presence of water instead of brine to afford the corresponding aldol products with anti-selectivity.

A fluorinated diamine organocatalyst is successfully applied in the aldol reaction of various aromatic aldehydes towards cyclic ketones.

SUA efficiently catalyzes the reaction between aldehydes and cyclic ketones to yield anti-aldol products with high enantioselectivity.

The new fluorous sulfonamide PFSA promotes effectively the aldol reaction at room temperature and in a shorter time compared to the diamine precursor.

The treatment of 6-chloroindolo[3,2-c]quinoline 6 with NaH–MeI led to methylation at N-11, forming 8, while the reaction of 6 with MeI with heating gave the corresponding 5-methylated quinolinium s...

Primary amides were easily prepared in 22–99% yields from the corresponding carboxylic acids 1 or 5 with NH4Cl via activation with ClCO2Et and Et3N. The enantiomers of the corresponding primary ami...

The activation and amidation step proceeds at low temperature, thus avoiding racemization of the products.

Thermodynamically controlled deracemization of some acyclic ketones bearing a chiral center at the position α to the carbonyl group was satisfactorily achieved. Acyclic ketones with high optical purities could be isolated after treatment of the racemic ketones with base in aqueous MeOH in the presence of (–)-(2R,3R)-trans-2,3-bis(hydroxydiphenylmethyl)-1,4-dioxaspiro[5.4]decane (1a). The efficiency of the deracemization was appreciably influenced by the ratio of H2O/MeOH used as solvent.

A convenient synthesis of δ,γ-unsaturated amino acids has been developed. After a mixture of ( R )- tert -butanesulfinamide and glyoxylic acid with molecular sieves in CH 2 Cl 2 was stirred for 42 h at room temperature, allylboronic acid pinacol ester was added to the mixture to give ( R )-2-(( R )- tert -butanesulfinamido)pent-4-enoic acid with high diastereoselectivity. The corresponding reaction of ( Z )-crotylboronic acid pinacol ester produced no product; however, that of ( E )-crotylboronic acid pinacol ester produced (2 R, 3 S )-2-(( R )- tert- butylsulfinamido)-3-methylpent-4-enoic acid with excellent diastereoselectivity.

γ-Fe2O3 and α-Fe2O3 with BET surface areas of 253 and 148 m2/g, resp., are synthesized by thermal treatment of γ-FeOOH or α-FeOOH precursors at 400 °C for 2—3 min.

The title compounds are prepared at 900—1100 °C and 5 GPa and characterized by single crystal XRD and magnetic measurements.

A convenient protocol for the condensation of carboxylic acids with unprotected α-amino acids via activation by ethyl chloroformate and triethylamine is presented.

The dimethoxybenzyl group represents an optimal protective group for the secondary amide (γ-lactam) moiety of an isoindolinone ring with an extraordinarily high polarity and difficult handling characteristics.

Best results for the synthesis of bicyclo[3.3.0]octane derivatives by cyclization of siloxydienynes are achieved using rhenium(I) catalysts under photoirradiation conditions.

α-Benzocycloalkenones in general form benzocycloalkadienes when they are subjected to reactions with neopentyl glycol or other alkanediols under forced conditions.

Novel C 2 -symmetric chiral bisoxazoline ligands with four asymmetric centers were readily synthesized from the two enantiomers of tartaric acid and several aminoacids via the corresponding bis(β-hydroxylamide)s and dimesylates as successive intermediates. With these novel chiral bisoxazoline ligands, rhodium(I)-catalyzed hydrosilylation of acetophenone was carried out and the effects of the combination of the four asymmetric centers as well as the substituent on oxazoline ring of the ligands on the reaction were studied.

Enantioselective synthesis of (–)-malyngolide (1) was accomplished by employing diastereo-selective addition of nonylmagnesium bromide to the 2-acylfuran derivative (4), followed by a ring transformation of the resulting optically active 2-furylalcohol (5) to give the pyranone derivative (7) as key steps.

The electrochemical calorimetry of the electrolysis of D2O has been carried out using a Pd cathode in an undivided, open cell fashion, together with measuring the total volume of the evolved gases....

The first asymmetric cyclopropanation of 1-alkenylboronic esters was realized by diastereofacial selective Simmons-Smith reaction of the esters modified by enantiomerically pure diols such as tetramethyltartar-amide. Subsequent oxidation of the resulting cyclopropylboronates gave optically active 2-substituted cyclopropanols in 73-94% ee. These reactive compounds possess high synthetic potential

The Diels-Alder adduct of 1,1-dicyclopropylspiro[2.4]hepta-4,6-diene (2a) with TCNE underwent unique rearrangement to give an imine derivative, whose formation may be explained by retro-Diels-Alder...

In order to elucidate the absolute configuration of C-15 in natural hyptol, methyl (15S)-12,16-dihydroxy-8,11,13-abietatrien-18-oate and its (15R)-epimer were transformed into (15S)-12,16-epoxy-11,14-dihydroxy-8,11,13-abietatrien-7-one (1a) and its (15R)-epimer (1b), respectively. The synthetic 1a w as identical to natural hyptol. Thus, the stereochemistry of C-15 in the natural compound was conclusively assigned as S-configuration.

(+)-8,11,13-Abietatriene was converted into (15R)-16-hydroxyferruginol (1a) and its (15S)-epimer (1b) by the introduction of hydroxyl groups at the C-12 and C-16 positions.

Esterification of Fmoc amino acids to 4-alkoxybenzyl alcohol polystyrene through acid chlorides was achieved in high yield with practically no racemization. This reaction is especially effective for the rapid anchoring of amino acids which have bulky side chains.

Selenation of 2-bromonaphthoquinone with an areneselenolate ion generated from bis(2-methoxy-carbonylphenyl) diselenide, chlorodiphenylphosphine, and LiOH afforded 2-[(2-methoxycarbonylphenyl)seleno]-1,4-naphthoquinone from which 12H-benzo[b]naphtho[2,3-e]selenin-6,11,12-trione was synthesized. 1,4-Dimethoxy-2,3-dimethyl-10H-dibenzo[b,e]selenin-10-one was prepared starting from 6-bromo-2,3-dimethylbenzoquione through the selenation and cyclization steps.

Selective and potent HIV protease inhibitors containing allophenylnorstatine [Apns; (2S, 3S)-3-amino-2-hydroxy-4-phenylbutyric acid] as a transition-state mimic were designed and synthesized. Among them, conformationally constrained tripeptide derivatives, kynostatin (KNI)-227 and -272 (Fig. 1), exhibited highly potent antiviral activities against a wide spectrum of HIV isolates. Ready availability due to the simple synthetic procedure and the excellent antiviral properties indicate that KNI-227 and KNI-272 are promising candidates as selective anti-AIDS drugs.

The first catalytic, enantioselective Simmons-Smith cyclopropanation of an allylic alochol has been achieved by the reaction of an allylic alcohol with Et 2 Zn and CH 2 I 2 in the presence of a catalytic amount of chiral disulfonamide 1 .

Carboindation of alkynols by allylic indium sesquihalides proceeded in DMF at 100 – 140 °C via a syn-addition; yomogi alcohol was prepared in onepot by this method.

Trifluoromethyl, heptafluoropropyl and chlorodifluoromethyl substituted but-2-en-4-olides have been prepared both from 2-trimethylsiloxyfuran by fluoroalkylation with the corresponding bis(fluoroalkanoyl) peroxide and from 2-fluoroalkylfuran by oxidation with m-nitrobenzenesulfonyl peroxide. 4-Difluoromethylbut-2-en-4-olide was also prepared by chlorodifluoromethylation of 2-methoxyfuran followed by reduction of the chlorine. The 4-trifluoromethylated butenolide, thus prepared, could be readily converted into the anion by treatment with weak base. The anion so formed then reacted with electron-deficient olefins to give 4,4-disubstituted butenolides.