161126-53-0

Basic information

• Product Name: 5-Isoxazolecarboxylicacid,4-formyl-3-methyl-,methylester(9CI)
• Synonyms: 5-Isoxazolecarboxylicacid,4-formyl-3-methyl-,methylester(9CI);methyl 4-formyl-3-methylisoxazole-5-carboxylate
• CAS NO: 161126-53-0
• Molecular Formula: C7H7NO4
• Molecular Weight: 169.13
• Product Categories: OXAZOLE
• Mol File: 161126-53-0.mol

Chemical Properties

• Appearance: /
• CAS DataBase Reference: 5-Isoxazolecarboxylicacid,4-formyl-3-methyl-,methylester(9CI)(CAS DataBase Reference)
• NIST Chemistry Reference: 5-Isoxazolecarboxylicacid,4-formyl-3-methyl-,methylester(9CI)(161126-53-0)
• EPA Substance Registry System: 5-Isoxazolecarboxylicacid,4-formyl-3-methyl-,methylester(9CI)(161126-53-0)

Safety Data

• Hazardous Substances Data: 161126-53-0(Hazardous Substances Data)

Upstream product

• 256473-75-3 tert-butyl 4-diethoxymethyl-3-methylisoxazole-5-carboxylate 
• 186581-53-3 diazomethane 
• 256473-81-1 4-formyl-3-methylisoxazole-5-carboxylic acid 
• 18107-18-1 diazomethyl-trimethyl-silane 

Relevant articles and documents

A New Entry to Isoxazolo[4,5-d]pyridazin-4(5H) [and 7(6H)]-ones from Functionalized Vinyl Sulfoxides

Isoxazolo[4,5-d]pyridazin-4(5H) [and 7(6H)]-ones can be respectively synthesized in a one-pot two-step synthetic sequence from 4 or 3-arylsulfinyl-5-alkoxyfuran-2(5H)-ones, involving their reactions with nitrile oxides and subsequent reflux with hydrazine hydrate into a 4:3 mixture of water/acetic acid. The 1,3-dipolar reaction takes place with complete regioselectivity, which is controlled by the position of the sulfinyl group at the dipolarophile, yielding, after desulfinylation and subsequent opening of the lactone ring, the two possible regioisomeric 3-substituted isoxazoles bearing formyl and carboxylic acid moieties at C-4 and C-5. These compounds, as well as their methyl esters, can be independently transformed into the corresponding isoxazolopyridazinones in high yields by reaction with hydrazine hydrate.

1,3-Cycloaddition of nitrile oxides to cyclic and open-chain 4-oxo-2- sulfinylbut-2-enoic acid derivatives

The reactions of tert-butyl (E)-4,4-diethoxy-2-p-tolylsulfinylbut-2- enoate with benzonitrile, acetonitrile, and bromoformonitrile oxides yield isoxazoles. However, (S5,S(s))- and (R5,S(s))-5-ethoxy-3-p- tolylsulfinylfuranones with benzonitrile oxide afford isoxazolines. The reactivity of the double bond as a dipolarophile is strongly increased by the sulfinyl group. This is also the case of the regioselectivity, which usually is opposite to that exhibited by dipolarophiles lacking the sulfinyl group. Electrostatic interactions seemingly explain this behaviour. The π-facial selectivity of the reactions with the cyclic dipolarophiles is dependent on steric effects, but some role seems to be exerted by electrostatic attraction.

SYNTHESIS OF ISOXAZOLES BEARING METHOXYCARBONYL AND FORMYL GROUPS BY 1,3-DIPOLAR CYCLOADDITION OF NITRILE OXIDES TO OLEFINIC AND ACETYLENIC DIPOLAROPHILES

The 1,3-dipolar cycloaddition of benzo-, bromoformo- and acetonitrile oxides to enamino ester (1) and acetylenic esters (2,3) afforded functionalized isoxazoles in moderate to good yields.Cycloadditions with the enamino ester (1) gave the corresponding me