Cyanamides synthesis

Dedman AJ, Owen AJ (1962) Calcium cyanamide synthesis. Part 4— the reaction CaO + CO2 = CaC03. Trans Faraday Soc 58 2027-2035... 

A neutral aqueous solution of cyanamide (synthesis 9), or a solution made very slightly alkaline with ammonia, is... 

Cyanamide, synthesis 9 Dicyanodiamide, synthesis 10 Barium thiocyanate, synthesis 5 Potassium ootacyanomolybdate (IV) 2-hydrate, synthesis 43 Zirconium hafnium phosphates, synthesis IOC... 

NaNOj Guano Coke-Oven Gas (NH4)2S04 Cyanamide Synthesis CaCNi Electric Arc Ca(NOj)2 Total N... 

The synthesis of these disubstituied thioureas takes place in three steps. First the alkyl bromide is prepared by the action of hydrobromic acid on the corresponding alcohol (518). Then the dialkylcyanamide is obtained by treatment at 25°C with calcium cyanamide. The yields are of the order of 30 to 60%. Thioureas are obtained in a third step from the cyanamide by reaction at 40 C with HjS in the presence of pyridine. Yields ranged from 57 to 90% (518),... 

The checkers used 16.8 g. of Eastman Kodak Company cyanamide (P1995) without further purification. A convenient method of preparing cyanamide from commercial calcium cyan-amide has been described. According to the submitters, an aqueous solution of crude cyanamide is satisfactory in the present synthesis and is obtained by adapting this published procedure as follows. 

Synthesis of l-guanyl-3-methylpyrazole (29) (86% yield) from pyrazole 13 and aqueous cyanamide has been claimed (94GEP4237687). 

Guanidine dearranges less readily than urea and yidds ammonia and cyanamide as would be expected from the familiar method for its synthesis. If it is heated with aniline, the cyanamide shows no tendency to combine with that substance but combines with itself, as it does in the absence of aniline, to form melamine. 

Like the Haber process for the synthesis of ammonia, this reaction represents a way of converting elemental nitrogen into a compound (nitrogen fixation). Moreover, calcium cyanamide reacts with steam at high temperature to yield ammonia,... 

A synthesis of variously substituted imidazo[l,2- ]imidazol-2-ones 448 was described. These compounds were prepared by cyclocondensation of ct-amino acid derivatives 447 with cyanamide (Equation 210) <1995JHC141>. 

An efficient synthesis of 2-amino derivatives 256 is depicted in Scheme 70 2-halopyridines are first Ar-alkylated with various halides under microwave activation and next reacted with cyanamide under basic conditions <1999T2317>. A rapid parallel synthesis of derivatives bearing a benzoyl substituent at C-3 based on this reaction has been described <2002SL1544>. 

Calcium cyanamid process, for ammonia synthesis, 11 114, 115 Calcium cyanide, 8 194-197 Calcium cyanide diammoniate, 8 195 Calcium dichromate, molecular formula, properties, and uses, 6 561t 5-Calcium disilicate monosulfate, phase in Portland cement clinker, 5 472t 5-Calcium disilicate monocarbonate, phase in Portland cement clinker, 5 472t Calcium disilicide, 4 530 8-Calcium disodium trialuminate, phase in Portland cement clinker, 5 472t Calcium doping, 23 842-844 Calcium P-alumina, 2 406t Calcium ethylenediaminetetraacetate, 7 596t... 

The synthesis of the oligomers involved the known reaction of isocyanates and cyanamide (Nl CN). For example, N-cyano-N -phenyl urea has been synthesized from phenyl isocyanate and an aqueous alkaline solution of cyanamide in high yield.(3) Recently, similar reactions were used to prepare various di-N-cyanourea compounds from diisocyanates. ( 1) These monomers were also synthesized directly by reacting diisocyanates with cyanamide at melt temperatures. 

In the conventional extension 24) of this synthesis to S-alkyhsothio-ureas, low yields of the expected biguanides were obtained. Curd, Rose et al. 128, 131) have improved this synthesis by performing the condensation under conditions which first convert the S-alkylisothiourea into the corresponding cyanamide (i.e. in non-hydroxylic organic media boiling above 100°, and in the presence of an alkali metal alkoxide). 

Reaction between an amine salt and cyanamide has been used successfully for the synthesis of many mono- and poly-alkylguanidines [84-95], and also of alkoxyguanidines [96, 97] and aryloxyguanidines [98]. The reaction is usually carried out in boiling water or ethanol for from 1 to 24 hours. Higher temperatures have been employed using sealed tubes [99,100] or butanol as a solvent [82,101]. 

The discovery of the imidazolinotte herbicides had its beginnings in a random screening test some 12 years ago. The phthalimide 1 prepared originally as an anticonvulsant at Cyanamid s Lederle Laboratories had sufficient herbicidal activity to warrant the synthesis of additional members of this series. One of these, the chloro analog was essentially devoid of herbicidal activity but had instead a pronounced... 

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