Formaldehyde → 2-methylene-4H-benzo[1,4]thiazin-3-one

HRID 851919Notes

Reaction equation

HRID 851919 reaction equation
C(OP([CH:9]1[C:14](=[O:15])[NH:13][C:12]2[CH:16]=[CH:17][CH:18]=[CH:19][C:11]=2[S:10]1)(=O)OCC)C.[CH2:20]=O.O.C[O-].[Na+]>CO>[CH2:20]=[C:9]1[C:14](=[O:15])[NH:13][C:12]2[CH:16]=[CH:17][CH:18]=[CH:19][C:11]=2[S:10]1

Participants

6

Reactant 4

HCID 712FormaldehydeHCID 962WaterHCID 10942334Sodium MethoxideHCID 12218600HCID 12218600, compound

Product 1

HCID 122186142-methylene-4H-benzo[1,4]thiazin-3-oneYield 72%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Conditions

Temperature
0 °C

Procedure

(3-Oxo-3,4-dihydro-2H-benzo[1,4]thiazin-2-yl)-phosphonic acid diethyl ester (12.2 mmol) is dissolved in 40 mL of anhydrous MeOH and formaldehyde (37%) in water (12.2 mmol) is added to the orange solution. NaOMe (2N in MeOH) (12.2 mmol) is added and the reaction is cooled down to 0° C. The solid that precipitates is filtered to give 2-methylene-4H-benzo[1,4]thiazin-3-one. Yield: 72%. 1H NMR (400 MHz, CDCl3): δ 9.03 (s, 1H), 7.06 (m, 2H), 6.94 (m, 1H), 6.81 (m, 1H), 6.80 (s, 1H), 5.62 (s, 1H). MS: (ES+): 178.2 [M+1].

Workup

  1. customThe solid that precipitates
  2. filtrationis filtered

Sources & evidence

ORD record
ord-37db4c858e9848958bb4a657b5943a3f
Source dataset
uspto-grants-2007_08
Patent number
US07253164B2

Reaction notes

Loading…