Imines, thione

In contrast to the 4-hydroxy isomers, the thermally stable 5-hydroxy-THISs add to the C=C bond of cyclopropenylidenes (4. 18, 27. 28). The adducts eliminate carbonyl sulfide, and the strained bond breaks resulting in ring-expansion with formation of pyridin-4-ones. -thiones, or -imines. or 4-alkylidenedihydropvridines (20, X = 0. S.NR. or CRR ) (Scheme 19). 

Besides being useful precursors to pyrroles pyridine-2-ones -4-ones, -4-thiones. and -4-imines 4-alkylidene-dihydropyridines thiophenes 1,2,4-triazoles thiapyrane-2-thiones, isoquinoline-3-ones isoben-zothiophenes and 4-mercaptoimidazolium hydroxide inner salts, mesoionic thiazoles are potentially useful in the construction of molecules with herbicidic (39). central nerve stimulating, and antiinflammatory properties (40,41). Application in dye synthesis has likewise been reported (42). 

Relatively few data are available on the NMR spectra of azolinones and related thiones and imines (Table 9). 

Azolinone derivatives and the corresponding thiones and imines are listed in Table 18 only substituted derivatives have been measured frequently. The chemical shifts of non-aromatic azole derivatives are given in Tables 19-21 relatively few data are available and these are generally for substituted derivatives rather than for the parent compounds. 

A -Thiazoline-2-thione 1,2,3-Oxadiazolin-5-imine — 118.4 128.9 114.0 CHCI3 79HC(34-1)388... 

A -1,3,4-Oxadiazoline-5-thione H NMR, 6, 428 (72CJC3079) A -l,3,4-Oxadiazolin-5-imine, 4,N-dimethyl-2-phenyl-... 

Tetrazol-5-imine, 2-methyl-dipole moment, 5, 795 (56JA4197) Tetrazoline-5-thione, 1-phenyl- C NMR, 5, 805 (77JOC3725)... 

Evans et al. reported that the bis(imine)-copper (II) complex 25, prepared from chiral bis(imine) ligand and Cu(OTf)2, is also an effective chiral Lewis acid catalyst [34] (Scheme 1.44, Table 1.18). By tuning the aryl imine moiety, the bis(2,6-dichlor-ophenylimine) derivative was found to be suitable. Although the endojexo selectivity for 3-alkenoyloxazolidinones is low, significant improvement is achieved with the thiazolidine-2-thione analogs, for which both dienophile reactivity and endojexo selectivity are enhanced. 

Imidazolidine-2-thiones functionalised on the four-position can be obtained by reaction of HN(CH3)R with n-butyllithium, followed by addition of carbon disulfide. The lithium thicarbamate can then by further lithiated and cyclisation occurs upon reaction of this species with an imine (S) [22],... 

Reaction of 2-cyanomethylpyridine with iV-(l-aryl-l-chloro-2,2,2-trifluoroethyl)-iV -(4-methylphenyl)carbodiimides, and with (1,1,2,2,2-pentachloro- and l,l-dichloro-2,2,2-trifluoroethyl)isocyanates or A-methoxycarbonyl-l,2,2,2-tetrachloro-, — l-chloro-2,2-trifluoroacetaldehyde imines afforded 3-aryl-4-cyano-l-(4-methylphenyl)imino-3-trifluoromethyl-2,3-dihydro-17/-pyrido[l,2-f]pyrimidines and 4-cyano-3-trichloro-, 4-cyano-3-trifluoro-17/-pyrido[l,2-4pyrimidin-l-ones, respectively <2004CHE47>. Refluxing 2-cyanomethylpyridine and iV-(l-aryl-l-chloro-2,2,2-trifluoroethyl)isocyanates in benzene furnished l-aryl-4-cyano-l-trifluoromethyl-l,2-dihydro-3//-pyrido[l,2-4pyrimidin-3-ones. However, when the solution of the isocyanate was added dropwise to the solution of 2-cyanomethylpyridine, and the reaction mixture was then treated with NEt at room temperature, the isomeric 3-aryl-4-cyano-3-trifluoromethyl-2,3-dihydro-l//-pyr-ido[l,2-dpyrimidin-l-ones were obtained. Reaction of l-(acetyl- and benzoylmethylene)-6,7-dimethoxy-l,2,3,4-tetra-hydroisoquinolines with PhCONCS yielded 1-acetyl-, 1 -benzoyl-9,10-dime thoxy-3-pheny 1-6,7-dihydro-2//-pyrimido[6,l- ]isoquinoline-2-thiones <2003SL2369>. 

Structures of 3-[(4-methylphenyl)amino]-47/-pyrido[l,2-tf]pyrazine-4-thione, iV-tosyl-3-[(4-methylphenyl)a-mino]-4//-pyrido[l,2-tf]pyrazine 4-imine, and 246 were confirmed by X-ray investigations <1999JPR332>. The stereostructures of (4A,llaA)-lla-ethoxycarbonylT,3,4,6,lla-hexahydro-l,3,4,6,ll,lla-hexahydro-4-methox-ycarbonyl-l-oxo-[l,4]oxazino[4,3-A isoquinoline <1995ZK787>, 2//-pyrazino[l,2- ]isoquinolinc-l,4-dione 247 <2001TL543>, 4-benzyl-2-methyl-1,3,4,6,7,11 b-hcxahydro-2//-pyrazino[2,l -zz] isoqu incline-3,6-dione... 

The solid phase parallel synthesis of tetrahydroim idazo[ 1,2-a] [ 1,3,5J tri azep i n-2-thiones and 2-imines has been reported starting from resin-bound peptides <06JCO127>. Pyrazolo[T,5 l,6]pyrimido[4,5-cfjpyridazinones with potent and selective phosphodiesterase 5 (PDEj) inhibitory activity have been described <06JMC5363>... 

Thermolytic and photolytic transformations are reported for several diphenyl cyclopropenone imines and diphenylcyclopropene thione. 

Heating of a solution of 5-ethyl-3-phenyl-l,3,4-thiadiazol-2(377)-imine 85 in aq. NaOH to 80°C for 5h gave the 5-ethyl-2,3-dihydro-2-phenyl-l/7-l,2,4-triazole-3-thione 86 via Dimroth rearrangement (Scheme 7) <2002HCA1883>. Nucleophilic attack of the hydroxide on the electrophilic C-5 resulted in ring opening and, after rotation around the C(2)-N(3) bond and subsequent recyclization, triazole thione 86 formed. 

Some new spirothiadiazolepyrazolo[l, 4-e/][1,5] benzodiazepines have been reported by Rakilo et al. They are prepared by a regioselective 1,3-dipolar cycloaddition of a nitrile imine with pyrazolo[l,5,4-e/][ 1,5]benzodiazepine-thione <00H(53)571>. 

N-benzyladamantyl-2-imines, and 2-methyleneadamantanes were studied (352, 353). In particular, X-ray single-crystal analysis confirmed the configuration of the oxathiazoline 185, resulting from the favored attack of nitrile oxide on the 5-fluoroadamantane-2-thione. 2-Silyl-substituted oxathiazole 186 was synthesized by the 1,3-dipolar cycloaddition reaction of phenyl triphenylsilyl thioketone with 4-chlorobenzonitrile oxide (354). 

Heterocyclic Chemistry (CHEC-I). Reactivity of 1,3,2-dithiazole-5-ones, -thiones, -imines, and 1,3,2-oxathiazole-5-ones is also much more widely covered than in CHEC-I, their thermolysis, photolysis, oxidation, methylation, amination, hydrolysis, 1,3-cycloaddition, etc. are discussed. 

Fused 5-imino-l,2,4-dithiazolidine-3-thiones and 3-imines (100) take up nucleophiles on one sulfur atom, releasing the XCS structural unit of the heterocycle (Scheme 15) <85JCS(P1)1007>. Nonfused analogues (101) give up one sulfur atom to the nucleophile, the rest of heterocycle closing to form a 1,3-thiazetidine ring (102) (Scheme 16) <87ZC142>. 

The mesoionic compounds can be named in several ways. The systematic name for structure (4) is a 3-substituted anhydro-5-hydroxy-l,2,3,4-oxatriazolium hydroxide. Similarly, structure (5) is named a 3-substituted anhydro-5-thiolo-l,2,3,4-oxatriazolium hydroxide, and structure (6) a 3-substituted anhydro-5-amino-l,2,3,4-oxatriazolium hydroxide. Frequently used names for structure (4) are 3-substituted 5-hydroxy-1,2,3,4-oxatriazolium hydroxide inner salt Chemical Abstracts), 3-substituted l,2,3,4-oxatriazol-5-ylio oxide, or 3-substituted l,2,3,4-oxathiazolylium-5-olate. For practical purposes, the term mesoionic l,2,3,4-oxatriazol-5-one is often used. Analogously, (5) and (6) are named mesoionic l,2,3,4-oxatriazol-5-thione and mesoionic l,2,3,4-oxatriazol-5-imine, respectively. 

A general synthetic route to meso-ionic iV-acyl-l,3-thiazol-5-imines (108, R = Ph, = Me, R = Me or Ph, R = COPh) is provided by treatment of thiobenzamidoaminoacetonitriles, Ph-CS-NMe-CHR-CN, first with benzoyl chloride and then with aqueous alkali. Alternatively, the thiobenzamidoaminoacetonitriles and hydrogen chloride give the corresponding salts, which with benzoyl chloride and aqueous alkali give -acyl l,3-thiazol-5-imines Derivatives (108, R = SMe) have been obtained by treating 5-acylamino-4-thiazoline-2-thiones with methyl iodide and aqueous alkali. ... 

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