Synthesis and Some Chemical Behaviour of Certain Substituted Thiosemicarbazides

Three new thiosemicarbazides (1 a-c ) were prepared from N-[4-phenyl-5-(2-thienyl)-1,2,4-triazol-3-yl]mercaptoacetohydrazide. Reaction of (1 a-c) with the appropriate phenacyl bromide afforded thiazoline derivatives (2 a-i) whereas their reaction with chloroacetic acid or maleic anhydride gave the corresponding thiazolidine derivatives (3 a,b) and (4 a,b) . Cyclodesulfurization of (1 a-c) with DCCD in toluene yielded 5-substituted-amino-1,3,4-oxadiazoles (5 a,b) , while their dehydration with PPA gave the corresponding 5-substituted-amino-1,3,4-thiadiazoles (6 a-c) . Six representative compounds were tested for their in-vitro antimicrobial activity against some pathogenic microorganisms, some of them were proved to be active.     

The reaction of 4-amino-2-oxazolines with isocyanates and isothiocyanates. Synthesis and X-ray structures of polysubstituted 2-imidazolidinones, 1,3-oxazolidines and 1,3-thiazolidines

Reactions of 4-alkylamino-2-phenyl-2-oxazolines 1 with isocyanates and isothiocyanates provide unprecedented efficient and regioselective heterocycle-heterocycle transformations. Compounds 1 reacted rapidly with tosyl isocyanate yielding directly 3-alkyl-4-benzamido-1-tosyl-2-imidazolidinones 4 in almost quantitative yields. The corresponding ureido intermediates 2 were not isolable species. However, the reactions with non-sulfonylated isocyanates or isothiocyanates were slower, leading to the expected ureido and thioureido derivatives 5, which were easily and efficiently transformed to either polysubstituted 2-imino-1,3-oxazolidine or 2-imino-1,3-thiazolidine hydrochlorides 7, respectively, by treatment with hydrochloric acid. The possible reasons for this disparity in chemical behaviour are discussed. X-ray crystallographic structures for 4-benzamido-3-methyl-1-tosyl-2-imidazolidinone 4b, 4-[1-isopropyl-3-(4-nitrophenyl)ureido]-2-phenyl-2-oxazoline 5e, (Z)-3-benzyl-4-benzamido-2-phenylimino-1,3-oxazolidine hydrochloride 7a and (Z)-3-benzyl-4-benzamido-2-phenylimino-1,3-thiazolidine hydrochloride 7b have been determined.     

Synthesis and Reactions of 3‐Methylthiazolo[3,2‐a]Benzimidazole‐2‐Carboxylic Acid Hydrazide: Synthesis of Some New Pyrazole, 1,3‐Thiazoline, 1,2,4‐Triazole and 1,2,4‐Triazolo[3,4‐b]‐1,3,4‐Thiadiazine Derivatives Pendant to Thiazolo[3,2‐a]Benzimidazole Moiety

The reaction of 3‐methylthiazolo[3,2‐a]benzimidazole‐2‐carboxylic acid ethyl ester (1) with hydrazine hydrate gives the hydrazide 2 which reacts with CS₂/KOH to afford the potassium salt 3. Treatment of 3 with l‐aryl‐2‐bromoethanones 4a,b afforded the 1,3‐thiazoline derivatives 6a,b, respectively, while the reaction of 3 with hydrazine hydrate afforded 1,2,4‐triazole‐3‐thione derivative 9. The reaction of 9 with l‐aryl‐2‐bromoethanones 4a,b and with hydrazonyl chlorides 11a,b gave the 1,2,4‐triazolo[3,4‐b]‐1,3,4‐thiadiazine derivatives 10a,b and 12a,b, respectively. Treatment of hydrazide 2 with phenyl isothiocyanate in refluxing benzene gave the thiosemicarbazide derivative 16. The latter reaction gave 1,3,4‐oxadiazole derivative 17 when benzene was replaced by DMF. Cyclization of the thiosemicarbazide derivative 16 with NaOH resulted in the formation of the 1,2,4‐triazole‐3‐thione derivative 18.     

From Nef‐Isocyanide Adducts toward Functionalized 5‐Iminothiazolidines Containing Polarized CC Bonds

An efficient synthesis of alkyl 5‐(alkylimino)‐3‐aryl(alkyl)‐2‐(dicyanomethylene)‐4‐hydroxythiazolidine‐4‐carboxylates, containing polarized C?C bonds, via reaction of malononitrile, arylisothiocyanates, and the Nef‐isocyanide adducts, under basic conditions, is described.     

含P—H键螺环五配位磷化合物的加成反应（Ⅱ）

5-氢-1,9-二氧-4,6-二氮-5-膦螺[4,4]壬烷1在过量乙醇作用下与二硫化碳、异硫氰酸酯于室温下反应分别得到2-巯基二氢噻唑2和2-取代亚氨基四氢噻唑4_a或二氢噻唑4_b。此反应的机理为化合物1首先与乙醇进行酯交换形成三配位磷化合物,进而与不饱和键加成。     

Nucleophilic Substitutions of N-Acyl-4-Chloro-3-Thiazolidines with the Organometallic Selenolates LiSeMcp(CO)3, M = Mo,W. Crystal Structure of (RS)-3-Acetyl-4-[(η5-cyclopentadienyl)(tricarbonyl)selenolato-tungsten(II)]-2,2,5,5-tetramethyl-3-thiazolidine

Selenolato complexes of molybdenum(II) and tungsten(II) with biologically important thiazolidine N/S-heterocycles have been prepared via nucleophilic attack of LiSeMocp(CO)₃ or LiSeWcp(CO)₃ on N-acyl-4-chloro-thiazolidines, easily accessible by reaction of acyl chlorides with 3-thiazolines. The resulting complexes represent the first examples of organometallic derivatives of this class of heterocycles. They are stable under nitrogen in the solid state, but decompose in solution when exposed to air. An X-ray structure analysis of (RS)-3-acetyl-4-[(η⁵-cyclopentadienyl)(tricarbonyl)(selenolato)tungsten(II)]-2,2,5,5-tetramethyl-3-thiazolidine ( 2 a ) has been performed (C₁₇H₂₁NO₄SSeW, orthorhombic, Pbca, a = 1579.5(3) pm, b = 1138.7(2) pm, c = 2209.4(3) pm, Z = 8). It revealed a monomeric structure with a non-planar heterocyclic substituent in an envelope conformation and a W–Se bond length of 264.96(10) pm. ⁷⁷Se-NMR spectra displayed chemical shifts in the range –280 to –350 ppm. These values are consistent with earlier results on related complexes.     

Synthesis and biological evaluation of new 3-trifluoromethylpyrazolesulfonyl-urea and thiourea derivatives as antidiabetic and antimicrobial agents

Fluorinated pyrazoles, and benzenesulfonylurea and thiourea derivatives as well as their cyclic sulfonylthioureas 2-18 were prepared as hypoglycemic and antibacterial agents. The chemistry involves the condensation of 4-hydrazino benzenesulfonamide hydrochloride with 1-trifluoromethyl diketones 1 to give pyrazole derivatives 2 which upon bromination gave the bromopyrazole 3. Reaction of 2 or 3 with isocyanates and isothiocyanates gave the corresponding ureas 4 and 5 and thioureas 6 and 7. Cyclization of thiourea derivatives with ethyl bromoacetate, ethyl β-bromopropionate, 1,3-dichloroacetone and α-bromoacetophenone yielded the corresponding 4-oxothiazolidines 8 and 9, 4-oxo-5,6-dihydrothiazine 10, 5-oxo-4,5-dihydrothiazines 11 and 12 and thiazolines 13 and 14. Preliminary biological screening of the prepared compounds revealed significant antidiabetic and antibacterial activities.     

Einwirkung von Schwefel und Ethylenimin auf höhermolekulare symmetrische Ketone, 4. Mitt

The higher molecular ketones, undecanone-6 (1), tridecanone-7 (2), pentadecanone-8 (3), heptadecanone-9 (4) react with ethylenimine and sulfur to give 2,3-disubstituted 5,6-dihydro-1,4-thiazines (9–12) and 2,2-dialkylated thiazolidines (17–20). The reduction of9–12 with formic acid yields the corresponding thiomorpholines13–16 (70–90% yield).9–12 is also obtained by the reaction of -chloro ketones (5–8) and the sodium salt of cysteamine 30–75% yield); cysteamine reacts with1–4 to give the thiazolidines17–20 (37–53% yield).

Teil der DissertationJ. Stalschus, Techn. Hochschule Aachen, 1974.     

Synthesis and Biological Activity of Mercaptobenzoxazole Based Thiazolidinones and Their Arylidenes

Arylidenes of thiazolidines with mercaptobenzoxazole, namely[(aryl‐4‐oxo‐1,3‐thiazolidin)‐hydrazinoacetyl‐mercaptobenxazole]; (5‐arylidene)‐2‐aryl‐4‐oxo‐1,3‐thiazoliden hydrazinoacetyl‐mercaptobenxazole were synthesized. Their chemical structures have been confirmed by ¹H NMR, IR, mass spectra and also by microanalytical data. Antimicrobial evaluation was done by agar dilution method against three pathogenic bacteria viz. Bacillus subtilis, Escherichia coli and Klebsiella pneumoniae and three pathogenic fungi viz. Aspergillus niger, Candida albicans and Fusarium oxysporum. Among new derivatives evaluated, the chloro derivatives exhibited higher potency as compared to the standard drugs streptomycin (for bacteria) and griseofulvin (for fungi) against the tested organisms.     

Asymmetric synthesis of monocyclic β-lactams from l-cysteine using photochemistry

An asymmetric method to synthesize cis-configured β-lactams using photochemistry has been developed. Aerobic photo-oxidation of l-cysteine-derived thiazolidine hydroxamate esters afforded C-3 hydroxylated products which when cyclized and deprotected gave the corresponding N-protio monocyclic β-lactams.