ChemInform Abstract: THIOPHEN‐REIHE 7. MITT. CHLORMETHYLIERUNG DES 2,5‐DIMETHYL‐THIOPHENS

Kinetic resolution of primary 2-methyl-substituted alcohols via Pseudomonas cepacia lipase-catalysed enantioselective acylation

“…38 2-Methyl-5-(2-thienyl)pentan-1-ol 4a. 60 Using a slightly modified version of the method described for the preparation of 2-methyldodecanoic acid, 61 2-methyl-5-(2-thienyl)pentanoic acid 59 was prepared. n-Butyllithium in hexane (1.6 M; 20.0 ml, 32.0 mmol) was added slowly (60 min) to a solution of dry diisopropylamine (4.5 ml, 32 mmol) in dry THF (25 ml) at Ϫ5 ЊC.…”

Synthesis of Fused Thiopyranthione and Thiophene Derivatives from 4,5-Dihydro-3-thiophene(and -3-furan)carbonitriles Having an Active Methylene Group at C-2 Position

“…22 Thus, the starting materials, heterocyclic α,β-unsaturated nitriles 3a−c, 4a−d, 5a−c, and 6a−d were synthesized by Wittig reaction of compounds 1a−c and 2a−d with (triphenylphosphoranylidene)acetonitrile and/or methyl (triphenylphosphoranylidene)acetate in refluxing toluene with 55−98% isolated yields (Scheme 1 and In the next step, we tried to construct fused thiopyranthiones 7−10 from compounds 3−6 and carbon disulfide [23][24][25]. These products 7−10 gave satisfactory elemental analyses and spectroscopic data (IR, 1 H NMR, 13 Finally, we also attempted Gewald reaction 26,27 of compounds 3, 5 and 6 with sulfur powder (Scheme 2). solvent, time, and substrate/base molar ratio.…”

“…In the course of our studies on heterocyclic β-enaminonitriles, 7−11 we became interested in the development of the methods for the synthesis of heterobicycles such as thieno [3,2-c]thiopyrans, 12,13 thiopyrano [4,3-b]furans, 14 thieno [3,4-b]thiophenes, 15−17 and thieno [3,4-b]furans. The synthesis of these compounds has been rarely described in the literature.…”

Modification of the Orientation of Substitution Reactions on Thiophene and Furan Derivatives

“…It was of interest to study the reaction of 2-acetylfuran (14) with bromine in the presence of an excess of aluminum chloride. According to E. V. Brown, (14) is brominated in the side chain when little or no catalyst is present 1671.…”

“…According to E. V. Brown, (14) is brominated in the side chain when little or no catalyst is present 1671. It is also known t68-711 that in the halogenation of furan derivatives having electronegative substituents in position 2, the u-directing effect of the ring oxygen (which evidently influences the substitution direction more strongly than the sulfur in thiophene) predominates.…”