摘要:
A process for the preparation of fluoroformates of the formula wherein R1 is a saturated or unsaturated, substituted or unsubstituted and primary or secondary aliphatic, a saturated or unsaturated, substituted or unsubstituted secondary cycloaliphatic or a substituted or unsubstituted aromatic or heteroaromatic, and n is equal to 1, 2 or 3, comprising reacting a corresponding chloroformate of formula I with an alkali metal fluoride in ethylene carbonate at a temperature wherein the ethylene carbonate is liquid whereby it is possible to very rapidly obtain the fluoroformates with excellent yields and high purity.
摘要:
The invention relates to a process for the preparation of 1-bromoethyl hydrocarbonyl carbonates, characterized in that anhydrous hydrobromic acid is reacted with a vinyl hydrocarbonyl carbonate of formula ##STR1## in which R denotes a saturated, substituted or unsubstituted C.sub.1 -C.sub.12 aliphatic radical or C.sub.5 -C.sub.24 alicyclic radical, or a substituted or unsubstituted aromatic radical, at a temperature between 10.degree. and 100.degree. C.The invention also relates to the new 1-bromoethyl hydrocarbonyl carbonates of formula: ##STR2## These carbonates are particularly sought after for introducing a carbonate group into a molecule.
摘要:
The invention relates to a new process for the preparation of carboxylic acid chlorides by phosgenation of the corresponding carboxylic acid in the presence of a catalyst.This process is characterized in that the said catalyst is chosen from the compounds represented by the formulae ##STR1## in which R.sub.1 to R.sub.6, which are identical of different, denote: aliphatic, alicyclic, araliphatic or aromatic radicals,or form, in pairs, with the nitrogen atom to which they are attached or with the N-C-N group, a 5- or 6-membered heterocyclic ring.The process applies to most carboxylic acids.The acid chlorides obtained are known and used to produce radical polymerization initiators or pesticides.
摘要:
Novel 2,2-dihalovinyl haloformates are described of general formula: ##STR1## in which: X is a chlorine or bromine atom;X.sub.1 and X.sub.2 are the same or different and are chlorine or bromine.The compounds are prepared by reaction of a 1,2,2,2-tetrahaloethyl haloformate of formula: ##STR2## in which: X.sub.1, X.sub.2 and X are as described hereinabove;X.sub.3 is chlorine or bromine and is always bromine when X.sub.1 and/or X.sub.2 is bromine andX.sub.4 is chlorine or bromine, with a metal such as zinc or magnesium in a solvent.The novel compounds are very useful for the preparation of 2,2-dihalovinyl carbonates and carbamates which may be used as insecticides or as comonomers.
摘要:
The subject of the invention is a new process for the preparation of alkyl thiochloroformates.The process according to the invention consists in reacting phosgene with a mercaptan in the presence of a catalyst which is a hexaalkylguanidinium chloride or the corresponding hydrochloride of general formula: ##STR1## in which R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5 and R.sub.6 represent alkyl radicals containing 1 to 4 carbon atoms and in which n may take either the value 0 or the value 1.The preferred catalysts are hexamethylguanidinium chloride and its hydrochloride.The process according to the invention enables very pure alkyl thiochloroformates to be obtained with milder operating conditions and simplified purification operations.
摘要:
Vinyl chloroformates are described of formula ##STR1## in which: R.sub.1 .dbd.R.sub.2 .dbd.Cl, Br or a saturated 1-4 carbon atom alkyl or together they form a cycloaliphatic ring of 4-8 carbon atoms;R.sub.3 .dbd.H when R.sup.1 or R.sup.2 .dbd.alkyl; saturated alkyl of 1-4 carbon atoms or aryl; ##STR2## in which R.sub.4 .dbd.R.sub.5 .dbd.alkyl of 1-4 carbon atoms or R.sub.3 forms with R.sub.2 a C.sub.5 -C.sub.8 ring which may have attached oxygen atoms. The process of preparation consists of reacting phosgene with the corresponding compounds containing alpha halogen and a carbonyl group. The products are very useful to obtain vinyl carbonates and carbamates.
摘要:
The invention relates to a process for the preparation of 1-bromoethyl hydrocarbonyl carbonates, characterized in that anhydrous hydrobromic acid is reacted with a vinyl hydrocarbonyl carbonate of formula ##STR1## in which R denotes a saturated, substituted or unsubstituted C.sub.1 -C.sub.12 aliphatic radical or C.sub.5 -C.sub.24 alicyclic radical, or a substituted or unsubstituted aromatic radical, at a temperature between 10.degree. and 100.degree. C.The invention also relates to the new 1-bromoethyl hydrocarbonyl carbonates of formula: ##STR2## These carbonates are particularly sought after for introducing a carbonate group into a molecule.
摘要:
The invention relates to a process for the preparation of N-carboxyanhydrides by reaction of the corresponding amino acid with phosgene, diphosgene and/or triphosgene in a solvent medium, characterized in that the reaction is a least partially carried out in the presence of an unsaturated organic compound which has one or more ethylenic double bonds, one of the carbon of at least one ethylenic double bond of which is completely substituted by substituents other than halogen atoms. The N-carboxyanhydrides are thus obtained with better yields and an improved purity.
摘要:
The invention relates to a novel process for the preparation of acyl isocyanates which consists in reacting oxalyl chloride with an N-trialkylsilylcarboxamide or an N,N-bis(trialkylsilyl)carboxamide. The process makes it possible to obtain acyl isocyanates in good yield, in particular acyl isocyanates derived from aliphatic amides, and under simplified reaction conditions.
摘要:
The invention relates to a new process for the preparation of 1-bromoalkyl hydrocarbyl carbonates.The carbonates according to the invention are prepared by reacting an alpha-chlorinated carbonate of formula ##STR1## with an anhydrous brominated compound of formula ZBr in which Z represents hydrogen, the group (CH.sub.3).sub.3 -Si-, the group ##STR2## or bromine if R.sub.2 is other than an aromatic radical, in the presence of a catalyst chosen from the group consisting of heteroaromatic amines, quaternary ammonium or phosphonium halides, hexasubstituted guanidinium halides, alkaline earth metal halides or alkali metal halides in combination with a complexing agent for their cation.The carbonates according to the invention find their preferential applications as blocking agents for some antibiotics or as agents for the synthesis of phosphorus-containing carbonates which can be used as insecticides.