Synthesis of heterocyclic compounds from 3‐acetyl‐3‐chloropropyl acetate

Abstract

The reaction of the potassium salt of 2‐mercaptobenzimidazole with 3‐acetyl‐3‐chloropropyl acetate afforded the novel heterocyclic compound 1. When solutions of 1 in deuteriodimethylsulfoxide or deuteriomethanol were allowed to stand at room temperatures for 15 minutes and 19 days, respectively, ring opening of 1 occurred to give the precursor, 3‐acetyl‐3‐(2‐benzimidazolthio)propyl‐1‐ol. The treatment of 1 with p‐fluorophenyl isocyanate furnished the carbanilate 2. The reaction of ammonium dithiocarbamate with the above chloroketone afforded the 2‐thiazolethione 3. Possible mechanisms and supporting nmr, ir, mass spectral data for 1–3 and single crystal X‐ray analysis for 2 are discussed.

A New Entry for Short and Regioselective Synthesis of [1,2,4]Triazolo[4,3-b][1,2,4]-triazin-7(1H)-ones

“…Its 1 H NMR spectrum showed, in addition to the aromatic proton multiplet, five characteristic signals at δ 1.40(t), 2.41(s), 3.92(s), 4.50(q), 11.5 (s) assignable to the CH 3 CH 2 OCO, CH 3 CO, =CH-and -NH-protons, respectively. The appearance of such signals and the absence of signals at δ 4.75 (1H) and 2.02 (3H) due to resonances of the HO and methyl protons expected for the ring tautomer 4 exclude the assignment of the latter structure to the products isolated [9]. The formation of 3 from 1 and 2 is analogous to the S-alkylation of 2,3-dihydro-6-substituted- [1,2,4]triazin-4(1H)-one derivatives [10].…”

Thiazolo[3,2-a]benzimidazoles: Synthetic Strategies, Chemical Transformations and Biological Activities

“…Thiazolo[3,2- a ]benzimidazoles 2 and 16 [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ] were obtained by the reaction of 2-mercaptobenzimidazoles 3 with various α-halo ketone derivatives 13 (14) which gave the corresponding acyclic intermediates 15 . Cyclization of the latter by acetic anhydride/pyridine mixture, polyphosphoric acid or sodium ethoxide gave compounds 16 ( Scheme 4 ).…”