Synthesis of heterocycles. Part II. New routes to acetylthiadiazolines and alkylazothiazoles

Abstract

Methylglyoxalyl chloride arylhydrazones (III) react with an ethanolic solution of thiourea to give 2‐amino‐4‐methyl‐5‐arylazothiazoles (XII) instead of the expected 2‐acetyl‐4‐aryl‐5‐imino‐Δ2‐1,3,4‐thiadiazolines (V) which were obtained from III and potassium thiocyanate. 3‐Thiocyanato‐2,4‐pentanedione (IV) coupled with diazotized anilines to give V. The postulated routes to formation of V and XII from III are given. Nitrosation of V gave the corresponding N‐nitroso derivatives (VI) which decomposed upon refluxing in dry xylene to give 2,4‐disubstituted‐Δ2‐1,3,4‐thiadiazolin‐5‐ones (VII). Boiling of either V or VI with hydrochloric acid gave the hydrochloride salt (VIII). The thiadiazolines V gave the respective N‐acyl derivatives (IX) and (X) with acetic anhydride and benzoyl chloride in pyridine.

HETEROAROMATIZATION WITH SULFONAMIDO PHENYL ETHANONE: PART (IV). SYNTHESIS AND ANTIMICROBIAL ACTIVITY OF NEW N-ETHYL-N-METHYLBENZENESULFONAMIDE, 1,3,4-THIADIAZOLE, 1,3,4-THIADIAZINE, 4-OXOTHIAZOLIDINE AND PYRAZOLO[5,1-c][1,2,4]TRIAZINE DERIVATIVES

“…IR spectrum of 11 showed absorption bands at 3169 cm -1 for NH group and 2262 cm -1 for CN group, while 1 H NMR spectrum of 11 showed singlet at δ 2.29 ppm for CH3-C=N, singlet at δ 4.26 ppm for CH2CN and singlet at δ 11.18 ppm for NH group. Interaction of hydrazonecarbodithioate derivative 7 with hydrazonoyl bromides 12a,b [28][29][30] in ethanol containing triethylamine gave the corresponding 1,3,4-thidiazole derivatives 15a,b, respectively. The formation of 15a,b can be rationalized via elimination of methylmercaptan from the corresponding cyclo adduct intermediates 14a,b, which is assumed to be formed from 1,3-dipolar cyclo addition of nitrileimines to the thiocarbonyl double bond.…”

Synthesis of New Derivatives of Heterocyclic Compounds Containing Pyridine, Pyrimidine and Triazole Ortho-Fused to Isoquinoline Moiety

“…Elemental analyses were carried out at the Micro analytical Center of Cairo University. 6,7-dimethoxy-3,4-dihydroisoqinoline-1-acetonitrile 1 (Osbond, 1951) and the hydrazonoyl halides 13a (Eweiss & Osman, 1980), 13b (Shawali & Abdelhamid, 1976) and 15 (Shawali et al 1975) were prepared as previously described.…”

Synthesis of New 3-Heteroarylindoles as Potential Anticancer Agents

“…All reactions were followed by TLC (silica gel coated aluminum sheets 60 F254, Merck, Merck & Co., Inc., Kenilworth, NJ, USA). Hydrazonoyl halides were prepared as reported in the literature [43][44][45][46]. To a mixture of 1-(1H-indol-3-yl)-3-(p-tolyl)prop-2-en-1-one (3a) (2.61 g, 10 mmol) and thiosemicarbazide (0.92 g, 10 mmol) in EtOH (20 mL), a catalytic amount of triethylamine (1 mL) was added, then heated under reflux for 6 h. The resulting solid was collected, washed with EtOH and recrystallized from acetic acid to give pure 5 as white solid (74% …”