3673-79-8Relevant articles and documents
A 1H NMR and molecular modelling investigation of diastereotopic methylene hydrogen atoms
Tormena, Claudio F.,Freitas, Matheus P.,Rittner, Roberto,Abraham, Raymond J.
, p. 279 - 283 (2002)
The 1H NMR spectra of methyl 3-bromo-2-methylpropionate (1a) and the corresponding chloro compound (2a) show no long-range coupling between the methyl and methylene protons. In contrast, in the analogous dihalocompounds, methyl 2,3-dibromo-2-methylpropionate (1b) and methyl 2,3-dichloro-2-methylpropionate (2b), one of the methylene protons exhibits a large 4JHH coupling (0.8 Hz) to the methyl group, but the other proton shows no observable splitting. This can be explained quantitatively by calculations of the conformational preferences in these compounds combined with the known orientation dependence of the 4JHH couplings. One conformer predominates in the dihalo compounds 1b and 2b, and this is responsible for the 4JHH coupling. In 1a and 2a all three conformers are populated and the 4JHH couplings average to zero. The technique is a potentially general method of unambiguously assigning diastereotopic methylene protons. Copyright
A paraquat emetic and preparation method
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Paragraph 0018-0040; 0042, (2019/04/04)
The invention relates to the field of organic synthetic technology, in particular to a paraquat emetic and preparation method, comprises the following preparation steps, S1, preparation of [...]; S2, the preparation of the etherification; S3, pyrimidine triazole; S4, PP796 preparation. The invention one-pot method for directly simple high yield of synthetic method is more suitable for industrial production technology, the process route and is simple, low cost, production and operation method is simple and convenient, high yield, the total yield to methacrylic acid methyl ester idea can reach 43.5% or more, the obtained product and luster is pure white, crystalline state is good, content ≥ 99%.
Technology for three-innovation synthesis of 2-amino-5-methyl-4-oxo-3-n-propyltriazolopyrimidine
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Paragraph 0015; 0029-0040, (2019/11/29)
The invention discloses a technology for synthesizing 2-amino-5-methyl-4-oxo-3-n-propyl-6H-triazolo-[1,5-a]pyrimidine. Methyl methacrylate and bromine are firstly subjected to an addition reaction toprepare methyl 2,3-dibromo-2-methylpropanoate, and then the methyl 2,3-dibromo-2-methylpropanoate and sodium methylate are etherified in a new suitable solvent to prepare methyl 3,3-dimethoxy-2-methylpropionate etherate; the etherate and 3,5-diamino-1,2,4-triazole, prepared from hydrazine hydrate and dicyandiamide under the catalysis of an acid, are condensed at an intermediate temperature of about 115 DEG C under the catalysis of an organic base to obtain a pyrimidotriazole compound; and the pyrimidotriazole material liquid and 1-chloropropane undergo a direct alkylation reaction in an inorganic or organic bas and a new solvent to obtain the 2-amino-5-methyl-4-oxo-3-n-propyl-6H-triazolo-[1,5-a]pyrimidine. The technology is improved by the three major innovations of improving the catalyticsynthesis conditions of the condensation ring closure of the pyrimidotriazole, optimizing the alkylation substitution reaction and the process technology of the pyrimidinetriazole and innovating theraw material of an alkylation reagent, so the technology has the advantages of great improvement of the yield, simplicity in operation, mild reaction conditions, and safety to devices and human bodies, the total yield of methyl methacrylate can reach 46.5% or above, and the obtained product has a white color and a good crystalline state, and has a content of 99% or more.
HETEROCYCLIC COMPOUND
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Paragraph 1444; 1658, (2016/06/28)
A compound represented by the formula (I): wherein each symbol is as described in the SPECIFICATION, or a salt thereof has a PDE2A inhibitory action, and is useful as a prophylactic or therapeutic drug for schizophrenia, Alzheimer's disease and the like.
