2 IMINO-5-CYANO

V. CYCLOPROPANES WITH IMINO, CYANO AND CARBONYL SUBSTI... 

N, C, H only (20) Amino, azido, imino, cyano, diazonium, guanidino... 

The same amino compounds also underwent reactions with a series of 3-cyano-4-imino- and 3-cyano-4-oxo-piperidines to yield 4-amino-5,0,7,8-tetrahydropyrido[4,3-d]pyrimidines. . A tetra-hydropyTido[4,3-prepared from 4-amino-l-henzyl-3-cyano-d -piperidine (134) hy a simple one-step preparation. This method is of general application for the preparation of fused pyrimidines and previous papers in this field are listed by Taylor. ... 

An approach to 2,3,5-triaryl-4-imino substituted 1,2,5-thiadiazolidin 5-oxides 242 is the cycloaddition reaction between A -(a-cyano-a-aryl)-methylanilines 240 and sulphinylanilines 241 (99SC(29)911). In this way a number of thiazoli-dine S-oxides 242 could be obtained in satisfactory yield (54-70%). 

A 9 1 mixture of 2,4-difluoro-4-pentafluoroethyl-3-trifluoromethyl-2//-, and 2,4-difluoro-2-pentafluoroethyl-3-trifluoromethyl-4//-, as well as 2-pentafluoroethyl-3-trifluoromethyl-4-oxo-4//-pyrido[l,2-n]pyrimidine were characterized by H, and NMR (00JFC105). 2-Trifluoromethyl-3-cyano-4-imino- and -4-oxo-4//-pyrido[l, 2-n]pyrimidines were characterized by and F NMR (00MI27). 

Acidic hydrolysis of 4-imino-3-cyano-2-trifluoromethyl-4//-pyrido[l,2-n]pyrimidines in boiling EtOH with aqueous hydrochloric acid afforded 4-0X0 derivatives (00MI27). 

Reaction of 2-aminopyridine with ethyl 2-cyano-3-ethoxy-3-methyl-, -3-ethyl-, -3-phenylacrylates and ethyl 2-ethoxycarbonyl-3-ethoxy-3-methyl-, -3-phenylacrylates in boiling xylene yielded 2-substituted 4/f-pyrido[l,2-u]pyrimidine-3-carbonitriles and -3-carboxylates (99MI7). Similar reactions of 2-aminopyridine with 2-cyano-3-ethoxyacrylonitrile and its 3-methyl, 3-ethyl, -3-phenyl derivatives in boiling MeCN afforded 4-imino-4//-pyrido[l,2-u]-pyrimidine-3-carbonitrile and its 2-substituted derivatives. 

Reaction of 3-amino-2-cyano-4-[(phenylamino)(methylthio)methylene]-2-pentenedioate (408) with a large excess of 1,3-propanediamine afforded ethyl 6-imino-l, 2,3,4-tetrahydro-6//-pyrido[l, 2-n]pyrimidine-9-carboxylate (409) as depicted in Scheme 16 (95JHC477). 

Reaction of 4-cyano-3-imino-2,3,5,6,7,8-hexahydro-l//-pyrido[l,2-c]pyr-imidin-l-one 169 with 2-chloroethyl isocyanate at ambient temperature and under reflux gave N-acylated 170 and tetracyclic derivative 171, respectively (95MI1). Similar reaction of 3-amino-4-cyano-2,4a5,6,7,8-hexahydro-l// pyrido[l,2-c]pyrimidin-1-ones 172 afforded tricyclic compounds 173. 

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>. 

Cyano-l,2,4-thiadiazole-5-carboximidate 5-Imino-A3-l,2,4-thiadiazoline 3,5-Bis(diphenylamino)-l,2,4-thiadiazole... 

Cycloaddition reactions between iV-sulfinylanilines and iV-(a-cyano-a-aryl)methylanilines 175 provide 2,3,5-tri ary IM-imino-2//,3//,5//-[ 1,2,5] thiadiazolidi no 1-oxides 176 in good yields (Equation 35) <1999SC911>. 

A new stable sulfenylating reagent 3-phenylsulfenyl-2-GV-cyano-imino)thiazolidine 57 has been described. It reacts with amines or thiols to give sulfenamides or disulfides in excellent yields. a-Sulfenylation of carbonyl compounds also proceeds smoothly and if an optically active 4-diphenylmethyl substituent is attached to the thiazolidine ring (58), the cyclic (3-ketoester 59 can be sulfenylated in high yield with an ee of 96% to give the sulfide 60 <00SL32>. 

Aryl-7-(4 -diethylamino-2 -methylphenyl)imino-6-methyl-pyrazolo[5,1-r] [1,2,4]triazoles 57 <2002ARK133> 7-ben-zylidenc-6-mcthyl-3-phenylimino-2//-pyrazolo[5,l-r [ 1,2,4]triazole 58 and 6-benzylidene-6-methyl-2-phenyl-3-phenyli-minopyrazolo[5,l -z][ 1,2,4]triazoIe 59 < 1998PS( 134/135)119> 3-phenyIamino(l//)pyrazolo[5,l -r 1,2,4]triazol-6-oI 60 and l-phenyl-3-phenylamino(l//)pyrazolo[5,l-r][l,2,4]triazol-6-ol 61 <1999EJC175> 6-amino-7-cyano-3-phenylpyra-... 

When the HCN contained 1-2 % mole of water the yields tended to increase exponentially with dose. This was due to the occurrence of a superimposed thermal reaction, which became faster as the radiation products accumulated and persisted after irradiation ceased. Hummel and Janssen attributed it to the hydrolysis of imino and cyano groups on the polymer chain. They suggested that the ammonia generated in this process reacted with HCN to form cyanide ions, which then initiated the polymerisation. 

In contrast to the above benzonitriles, 2-methylbenzonitrile (11.88) did undergo cyano hydrolysis, but by a very indirect route involving cytochrome P450 catalyzed hydroxylation of the 2-Me group to form 2-(hydroxyme-thyl)benzonitrile (11.89), followed by intramolecular nucleophilic addition. The cyclization reaction yielded an unstable imino ether derivative (11.90), which hydrolyzes to phthalide (11.91). The conversion of 2-(hydroxyme-thyl)benzonitrile to phthalide followed first-order kinetics with a f1/2 value of 2.8 h at pH 7.4 and 37° [124],... 

Bis-acceptor-substituted diazomethanes are most conveniently prepared by diazo group transfer to CH acidic compounds either with sulfonyl azides under basic conditions [949,950] or with l-alkyl-2-azidopyridinium salts [951] under neutral or acidic conditions [952-954]. Diazo group transfer with both types of reagents usually proceeds in high yield with malonic acid derivatives, 3-keto esters and amides, 1,3-diketones, or p, y-unsaturated carbonyl compounds [955,956]. Cyano-, sulfonyl, or nitrodiazomethanes, which can be unstable or sensitive to bases, can often only be prepared with 2-azidopyridinium salts, which accomplish diazo group transfer under neutral or slightly acidic reaction conditions. Other problematic substrates include amides of the type Z-CHj-CONHR and P-imino esters or the tautomeric 3-amino-2-propenoic esters, which upon diazo group transfer cyclize to 1,2,3-triazoles [957-959]. 

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