Azides, carbamoyl

Car ba my I Azide Carbamoyl Azide or Azidoformam-ide(called CarbaroidsSureazid Azidoameisensaure-amid or Kohlensaure-amid-azid in Ger),... 

As for the acetyl phosphate monoanion, a metaphosphate mechanism has also been proposed 78) for the carbamoyl phosphate monoanion 119. Once again, an intramolecular proton transfer to the carbonyl group is feasible. The dianion likewise decomposes in a unimolecular reaction but not with spontaneous formation of POf as does the acetyl phosphate dianion, but to HPOj and cyanic acid. Support for this mechanism comes from isotopic labeling proof of C—O bond cleavage and from the formation of carbamoyl azide in the presence of azide ions. 

The 1,3-dipolar cycloaddition of azides to alkynes is a versatile route to 1,2,3-tri-azoles. Different combinations of substituents on the azide and on the alkyne allow the preparation of diverse N-substitutcd 1,2,3-triazoles. Katritzky and Singh have described the synthesis of C-carbamoyl-1,2,3-triazoles by microwave-induced cydoaddition of benzyl azides to acetylenic amides (Scheme 6.220) [393]. Employing equimolar mixtures of the azide and alkyne under solvent-free conditions, the authors were able to achieve good to excellent isolated product yields by microwave heating at 55-85 °C for 30 min. In general, the triazole products were obtained as mixtures of regioisomers. Control experiments carried out under thermal (oil bath)... 

Bis(azide)—rubber resists, 15 157 Bis-(P-hydroxyethyl) terephthalate, 10 487 Bis(biphenyl) chromium(I) iodide, physical properties, 6 528t Bis(carbamoyl) peroxides, 18 477 Biscarbonato uraniumfVI) complexes, 25 431... 

Analysis of the reaction KIE using monodeuterated sulfamate 106 reinforces the proposed rhodium-nitrene model (Eq. 9). The ratio of H/D products 107/108 is a direct measure of the KIE and has been found to equal 1.5 0.2 by integration of the C NMR spectrum. An equivalent value is obtained for nitrene C-H insertion upon photolysis of a carbamoyl azide, and is taken as evidence for a nonlinear transition state. As noted previously, Muller s use of NsN=lPh with partially deuterated adamantane gives... 

The bicyclic meso-ionic 3-oxo-l,2,4-triazolo[4,5-a]pyridines (206) have been prepared by the following methods (i) the reaction of the hydrazines (207, X = H) with phosgene, (ii) heating the amide (207, X = CONH2) or the carbamate (207, X = COjEt), and (iii) alkylation or acylation of 3-oxo-l,2,4-triazolo[4,5-a]pyridine (208). The isomeric meso-ionic 2-oxo-l,3,4-triazolo[4,5-a]pyridines (209) are formed from the carbamoyl chlorides (210) and sodium azide. ... 

Two enantioselective syntheses of (+)-biotin (293) from L-cysteine were reported based upon the intramolecular 1,3-dipolar cycloadditions of carbamoyl azides 289 and 291 by Deroose and De Clercq (58) (Scheme 9.58). Thermolysis of the carbamoyl azides 289 and 291 gave the triazolines 290 and 292, respectively. Both 290 and 292 were converted into (+)-biotin (293) in several steps. 

Preparation of 1 -butyl-3-p-tolylsulfonylurea by the reaction of butyl-carbamoyl azide with sodium p-toluene sulfinate [104]. 

The preparation and chemistry of alkyl and aryl azides [6] and carbamoyl azides [7a, b] have been reviewed [7a]. References to the decomposition and addition of azides have been recently compiled by L Abbe [1]. 

RCON -+ RN = CO. The carbamoyl azides, as a group, were classified by Bertho (Ref 3) as resistant to the Curtius rearrangement. However, other work by Stolle (Ref 2) showed that while some members of this group (RL or Ra H and Ra or Ra alkyl/aryl) failed to become rearranged, others (Rt or Ra CjHs) did so. Scott et al offered a different interpretation for the resistance of carbamoyl azide to such change... 

Ar-(cr-Chlorobenzylidene)carbamoyl chloride (241 R = Cl) reacted with sodium azide in glyme to give the fused oxadiazole 242 in 52% yield, in addition to other products.328 The mechanism of this reaction is uncertain, but it is thought to involve the intermediacy of 241 (R = N3) and the triazolone 243. 

The 1,3-dipolar cycloaddition of azides to acetylenic amides is particularly difficult under conventional thermal conditions and extended reaction times of 14 h to 1 week have been reported32,33. Katritzky reported a microwave-mediated solvent-free variant ofthis procedure to give N-substituted C-carbamoyl- 1,2,3-triazoles in good to excellent yields in only 30 min (Scheme 3.19)34. 

Katritzky, A.R. and Singh, S.K., Synthesis of C-carbamoyl- 1,2,3-triazoles by microwave-induced 1,3-dipolar cycloaddition of organic azides to acetylenic amides, ]. Org. Chem., 2002,67, 9077-9079. 

Carbamoyl azides 582 (R = CON3) can be used as an aminating agent of alkenes at the allylic position, enamines and alkyl silyl enol ethers <2001T4623>. 

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