24285-39-0Relevant articles and documents
Preparation method of O-methyl isourea sulphate
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Paragraph 0012, (2016/12/01)
The invention discloses a preparation method of O-methyl isourea sulphate. Reaction is divided into two process, a first process comprises the steps of adding urea and dimethyl sulphate into a reactor, mixing, then adding water and sulphuric acid, and carrying out reaction in the first process; and a second process comprises the steps of directly adding calcium hydroxide solid into a reaction liquid obtained in the first process in the reactor for carrying out reaction in the second process, and adding methyl alcohol after the reaction in the second process is completed for carrying out recrystallization, and filtering, so that the product O-methyl isourea sulphate is obtained. The total yield of the reactions in the two processes is more than 80%, and mass content of the product O-methyl isourea sulphate is more than 98%. The preparation method of the O-methyl isourea sulphate has the advantages that the reaction process is a 'quasi-one pot method' reaction, technology is simple, raw materials are available, solvent usage amount is small, operation is easy and yield is high; meanwhile, calcium hydroxide is adopted as the catalyst, fewer three wastes are produced in a preparation process, and environmental protection is facilitated; and a byproduct calcium sulphate can be applied to cement production, and comprehensive cost is further reduced, thereby being applicable to industrialized production.
Process for the preparation of 9-deazaguanine derivatives
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Page 19, (2010/02/09)
Derivatives of 9-deazaguanine are prepared by reacting an aldehyde or ketone with a dialkylaminomalonate to form the corresponding enamine. The enamine is then reacted with a base to form a cyclic pyrrole. The cyclic pyrrole is reacted with an urea compound or a derivative of carbamimidoic acid to provide a protected guanidino compound. The guanidino is converted to the desired 9-deazaguanine derivative by reacting with trifluoracetic acid or with an alkoxide or hydroxide followed by neutralization with an acid.
