Ethyl chloroformate → 6-Nitro-5-methyl-2-ethoxy-3,1-benzoxazin-4-one

HRID 22182

Reaction equation

HRID 22182 reaction equation
[N+:1]([C:4]1[CH:5]=[CH:6][C:7]([NH2:14])=[C:8]([C:12]=1[CH3:13])[C:9]([OH:11])=[O:10])([O-:3])=[O:2].Cl[C:16]([O:18][CH2:19][CH3:20])=O>N1C=CC=CC=1>[N+:1]([C:4]1[CH:5]=[CH:6][C:7]2[N:14]=[C:16]([O:18][CH2:19][CH3:20])[O:10][C:9](=[O:11])[C:8]=2[C:12]=1[CH3:13])([O-:3])=[O:2]

Participants

4

Reactant 2

HCID 10928Ethyl chloroformateHCID 152831726-Amino-2-methyl-3-nitrobenzoic acid

Product 1

HCID 152831736-Nitro-5-methyl-2-ethoxy-3,1-benzoxazin-4-oneYield 79%

Reagents, catalysts & solvents 1

HCID 1049PyridineSolvent

Procedure

A solution of 4.0 g (20.4 mmoles) of 5-nitro-6-methyl-2-aminobenzoic acid in 50 mL of dry pyridine was cooled in an ice-water bath under inert atmosphere. Ethyl chloroformate (Aldrich), 10 mL (105 mmoles), was added dropwise over a 15 minute period. A mild exotherm was observed and a solid separated from solution immediately upon addition. The suspension was stirred at room temperature under inert atmosphere overnight. Approximately half the pyridine was removed in vacuo, and the residual mixture poured over ice. The precipitated solid was collected and air-dried. 4.0 g (79% yield) 6-nitro-5-methyl-2-ethoxy-3,1-benzoxazin-4-one was obtained. NMR (DMSO-d6): 1.37(t,3H,J=7.2 Hz), 2.71(s,3H), 4.50(q,2H,J=7.2 Hz), 7.40(d,1H, J=9.0 Hz), 8.19(d,1H,J=9.0 Hz). IR(nujol): 1765 cm-1 (lactone carbonyl). MS(m/z): 250(M+).

Workup

  1. customa solid separated from solution immediately upon addition
  2. customApproximately half the pyridine was removed in vacuo
  3. additionthe residual mixture poured over ice
  4. customThe precipitated solid was collected
  5. customair-dried

Sources & evidence

ORD record
ord-7a5418f062a74240945f6ad1b316d8b0
Source dataset
uspto-grants-1995_06
Patent number
US05428021

Linked notes

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