Cyanamides cyclic

The acylation of enamines derived from cyclic ketones, which can lead to the acyl ketone or ring expansion (692-694), was studied by NMR and mass spectroscopic analysis of the products (695,696). In a comparative study of the rates of diphenylketene addition to olefins, a pronounced activation was observed in enamines (697). Enamine N- and C-acylation products were obtained from reactions of Schiff s bases (698), vinylogous urethanes (699), cyanamides (699), amides (670,700), and 2-benzylidene-3-methylbenzothiazoline (672) with acid chlorides, anhydrides, and dithio-esters (699). 

A convenient way of obtaining secondary amines without contamination by primary or tertiary amines involves treatment of alkyl halides with the sodium or calcium salt of cyanamide NH2—CN to give disubstituted cyanamides, which are then hydrolyzed and decarboxylated to secondary amines. Good yields are obtained when the reaction is carried out under phase-transfer conditions. The R group may be primary, secondary, allylic, or benzylic. 1, co-Dihalides give cyclic secondary amines. 

A second method is due to J. von Braun and consists in the addition of cyanogen bromide to tertiary cyclic bases.1 In the unstable addition product a C—N-linkage is broken and at the same time the bromine wanders to a new position. A brominated derivative of cyanamide is produced and this, on hydrolysis, yields a secondary amine which can be broken down further, e.g. 

If thymidylic acid is heated with cyanamide at pH 3, oligomers, for the most part cyclic, are formed, presumably via activated phosphate intermediates such as (68).107 On addition of acid salts, the same reactions can be realized at neutral pH.108... 

The strongly acidic character of cyanamide, compared with simple amines, results in its facile dialkylation by a range of reagents [24], Reaction with a,(o-dihalogeno compounds leads to cyclic products (Table 5.4). 

Various alkyl-substituted crown ethers have been prepared by cyclic addition across a double bond (e.g. bromination (77S854) or oxymercuration (80CC925)). Similarly, displacement of oligoethylene glycol dichlorides by cyanamide yields V-cyano monoaza crown ethers (81TL4105). 

The active hydrogens of pseudoureas react with various reagents, such as sodium hypochlorite [72], acyl halides [73], sulfonyl halides [19], isocyanates [26], isothiocyanates [26, 74] cyanamide, [75] and esters [76], to give linear or cyclic derivatives as shown in Scheme 2. 

CV, see Cyclic voltammetry CVD, see Chemical vapor deposition Cyanamides, germylated, reactions, 3, 736 Cyanides... 

Cyclic addition reactions of 16a with diynes or cyanamide are interpreted as being initiated by an electrophilic attack of the cyanamide or the terminal carbon atom of a C=C bond. Both result in ring expansion and the formation of 2,4-As,As-diphosphapyridine 39 <1998ZNB443> or l,3-A5,A5-diphosphabenzenes 40, respectively (Scheme 10). The diyne reaction is not limited to conjugated systems. 1,5-Hexadiyne and 1,7-octadiyne can be used as well <1997JOM(529)223>. 

Cyclic oligomers of dimesylgennylcarbodiimide, (Mes2GeNCN) , where n = 3 and 4 are synthesized from dimesylchlorogermanium with silver cyanamide in the presence of tri-ethylamine or using lithium cyanamide. ... 

Germaniumdicarbodiimide is obtained similarly from GeCl4 and bis(trimethylsilyl)-carbodiimide. Also, cyclic oligomers of dimesitylgermaniumcarbodiimide are obtained from dimesityldichlorogermanium and cyanamide in the presence of triethylamine or... 

SYNS AC 47470 AMERICAN CYANAMID CL-47470 CL-47,470 CYCLIC PROPYLENE piETHOXYPHOS-PHINYL)DITHIOIMIDOCARBONATE CYTROLANE p,p-DIETHYL CYCUC PROPYLENE ESTER of PHOSPHONODITHIOIMIDOCARBONIC ACID DIETHYL (4-METHYL-l, 3-DITHIOLAN-2-YLIDENE)-PHOSPHOROAMIDATE EI-47470 DENT25,991 MEPHOSFOLAN (4-METHYL-l,3-DITHIOLAN-2-YLIDENE)PHOSPHORAMIDIC ACID, DIETHYL ESTER... 

SYNS AC-43064 AMERICAN CYANAMID AC 43,064 CL-43,064 CYALANE CYCUC ETHYLENE (DIETHOXYPHOSPHINOTHIOYL)DITHIOIMIDOCARB ONATE CYCLIC ETHYLENE ESTER of (DIETHOXYPHOSPHINOTHIOYL)DITHIOIAnDOCARB ONIC ACID CYLAN CYOLAN CYOLANE INSECTICIDE 2-(DIETHOXYPHOSPHINYLIMINO)-1,3-DITHIOLANE 0,0-DIETHYL l,3-DITHIOLAN-2-... 

By treatment of acyclic and cyclic alkenes with cyanamide and A-bromosuccinimide, the corresponding /3-bromoalkylcyanamides were obtained in moderate to good yield via anti addition to the double bond, as shown for cholestane derivatives, e.g., 367-68, and cyclic, e.g., 470, and acyclic alkenes, e.g., 5 and 670... 

The iodocyclization of acyclic unsaturated isoureas containing (S )-phenylethylamine as the chiral auxiliary gave chiral cyclic isoureas, which are masked 1,2-diamines. Starting from (S)-phenyl-ethylamine, the corresponding cyanamide was easily obtained, which was then converted, after allylation, to the corresponding isourea. The iodocyclization of the isourea derived from (S)-phenylethylamine afforded an equimolar diastereomeric mixture of 4,5-dihydroimidazoles 4 in 90% yield, which were easily separated by chromatography167. 

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