Phosphorus oxychloride → 5-Chloro-2-methylpyrazolo[1,5-a]pyrido[3,4-e]pyrimidine

HRID 1833342Notes

Reaction equation

[CH3:1][C:2]1[CH:15]=[C:5]2[NH:6][C:7](=O)[C:8]3[CH:13]=[N:12][CH:11]=[CH:10][C:9]=3[N:4]2[N:3]=1.P(Cl)(Cl)([Cl:18])=O>>[Cl:18][C:7]1[C:8]2[CH:13]=[N:12][CH:11]=[CH:10][C:9]=2[N:4]2[N:3]=[C:2]([CH3:1])[CH:15]=[C:5]2[N:6]=1

Participants

Reactant 2

HCID 24813Phosphorus oxychloride

HCID 1361423592-Methylpyrazolo[1,5-a]pyrido[3,4-e]pyrimidin-5(4H)-one

Product 1

HCID 213891855-Chloro-2-methylpyrazolo[1,5-a]pyrido[3,4-e]pyrimidine

Procedure

200 g. of 2-methylpyrazolo[1,5-a]pyrido[3,4-e]-pyrimidin-5(4H)-one of Example 1c are refluxed with 800 ml. of phosphorus oxychloride overnight. The excess phosphorus oxychloride is removed in vacuo and the oily residue decomposed by pouring on ice. The acidic aqueous solution is made alkaline with sodium hydroxide. The precipitated 5-chloro-2-methylpyrazolo[1,5-a]pyrido[3,4-e]pyrimidine is filtered off, yield: 143 g. (66%); m.p. 169.8° (ethyl acetate).

Workup

customThe excess phosphorus oxychloride is removed in vacuo
additionby pouring on ice
filtrationThe precipitated 5-chloro-2-methylpyrazolo[1,5-a]pyrido[3,4-e]pyrimidine is filtered off

Sources & evidence

ORD record: ord-17fc6805ef334857b62c9c421f655886
Source dataset: uspto-grants-1978_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US04066645

Reaction notes

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