Electric Literature of 139756-02-8, These common heterocyclic compound, 139756-02-8, name is 4-Amino-1-methyl-3-N-propyl-1H-pyrazole-5-carboxamide, its traditional synthetic route has been very mature, but the traditional synthetic route has various shortcomings, such as complicated route, low yield, poor purity, etc, below Introduce a new synthetic route.
General procedure: We intended to synthesize compounds based on 1H-pyrazolo[4,3-d]pyrimidin-7(6H)-one scaffold by using microwave assisted protocol (Scheme 1). In this direction we started the studies for optimization of synthesis of 5-(2-ethoxyphenyl)-1-methyl-3-propyl-1H-pyrazolo[4,3-d]pyrimidin-7(6H)-one 3a. The optimization studies were initiated by screening of different oxidizing agents as depicted in Table1, see Supplementary data using DMSO:Water in 1:1 proportion to see the conversion in desired product. Amongst all oxidants, the best result was observed with K2S2O8, in equivalence studies for catalyst, 3eq. of catalyst has given maximum yields (Table1, see Supplementary data). Therefore, all reactions were conducted using this condition after optimization of catalyst. However, oxone has also given the product 3a with minor yields. After screening of the catalyst we started study of selectivity for solvent that could affect the formation of 5-(2-ethoxyphenyl)-1-methyl-3-propyl-1H-pyrazolo[4,3-d]pyrimidin-7(6H)-one 3a. The solvent screening was carried out to find out the best conversion, the mixture of DMSO:H2O in 1:1 proportion has given the best results with excellent yields (Table2, see Supplementary data). The microwave protocols were optimized for this reaction as mentioned in Table 3, see Supplementary data; the reactions carried under different microwave Watt powers have given varied results. Wherein, entry 3(b) (Table3, see Supplementary data) was found to be the best condition for maximum conversion. A series of compounds based on 1H-pyrazolo[4,3-d]pyrimidin-7(6H)-one scaffold was synthesized using these optimized conditions, wherein, all kind of substrates with diversity around aryl ring were chosen for conversion and in all cases products obtained in good to excellent yields (Table1).
Statistics shows that 4-Amino-1-methyl-3-N-propyl-1H-pyrazole-5-carboxamide is playing an increasingly important role. we look forward to future research findings about 139756-02-8.
Reference:
Article; Reddy, G. Lakshma; Guru, Santosh Kumar; Srinivas; Pathania, Anup Singh; Mahajan, Priya; Nargotra, Amit; Bhushan, Shashi; Vishwakarma, Ram A.; Sawant, Sanghapal D.; European Journal of Medicinal Chemistry; vol. 80; (2014); p. 201 – 208;,
Pyrazole – Wikipedia,
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