Synthesis of 2-Alkoxy-Substituted Thiophenes, 1,3-Thiazoles, and Related S-Heterocycles via Lawesson's Reagent-Mediated Cyclization under Microwave Irradiation:  Applications for Liquid Crystal Synthesis

One-Pot Chemoenzymatic Multicomponent Synthesis of Thiazole Derivatives

“…The model reaction and yields are shown in Scheme 1 and Table 1. Eight candidates such as trypsin from porcine pancreas (PPT), α-amylase from hog pancreas, diastase from Aspergillus oryzae, α-amylase from Aspergillus oryzae, lipase AT30, Amano lipase M from Mucor javanicus, and bovine serum albumin (BSA) were screened ( Table 1, entries [1][2][3][4][5][6][7][8]. The yield of product was the monitored parameter to evaluate the catalytic activity of enzymes.…”

“…Aryl-substituted thiazoles are also important functional materials in applications such as fluorescent dyes and liquid crystals [6]. Thiazoles have traditionally been synthesized by the Hantzsch synthesis [7,8], which suffers from some disadvantages such as long reaction times, low yields and harsh reaction conditions.…”

Thiadiazoles

“…Moreover, some 2,5-diaryl-1,3,4-thiadiazoles have been prepared in 74-91% yields using Lawessons reagent and microwave irradiation in the absence of solvent for 3-8 min [296]. Thus, for example, 2-phenyl-5-m-tolyl-1,3,4-thiadiazole (580) was prepared in 91% yield from of a mixture of 579 and Lawessons reagent (LR) (Scheme 14.160) [297].…”

Efficient Synthesis of Functionalized Thiazoles from Acid Chlorides, Tetramethylthiourea, Ethyl Bromopyruvate, and Ammonium Thiocyanate

“…A large number of thiazoles obtained from microbial and marine origins exhibit important biological effects such as antitumor, antifungal, antibiotic, and antiviral activities [1]. Synthetic thiazoles also show a wide variety of biological activity [2], while others have found application as liquid crystals [3] and cosmetic sunscreens [4]. The classical method for the synthesis of thiazoles is the Hantzsch process, in which an a-haloketone is condensed with a thioamide [5].…”