198839-96-2

Basic information

• Product Name: 4-deuterio-1-methyl-5-phenylpyrazole
• Synonyms: 4-deuterio-1-methyl-5-phenylpyrazole
• CAS NO: 198839-96-2
• Molecular Weight: 159.195
• Mol File: 198839-96-2.mol
• Article Data: 1

Chemical Properties

• CAS DataBase Reference: 4-deuterio-1-methyl-5-phenylpyrazole(CAS DataBase Reference)
• NIST Chemistry Reference: 4-deuterio-1-methyl-5-phenylpyrazole(198839-96-2)
• EPA Substance Registry System: 4-deuterio-1-methyl-5-phenylpyrazole(198839-96-2)

Safety Data

• Hazardous Substances Data: 198839-96-2(Hazardous Substances Data)

Upstream product

• 3463-27-2 1-methyl-5-phenyl-1H-pyrazole 
• 33603-87-1 β-chlorocinnamaldehyde 

Relevant articles and documents

Photochemistry of Phenyl-Substituted 1-Methylpyrazoles

Direct irradiation of 1-methyl-4-phenylpyrazole (2) in methanol results in regiospecific phototransposition to 1-methyl-4-phenylimidazole (4) and in photocleavage to (E)/(Z)-3-(N-methylamino)-2-phenylpropenenitrile (5) and (E)/(Z)-2-(N-methylaimno)-1-phenylethenyl isocyanide (6). Deuterium labeling confirms that the phototransposition occurs via the P4 permutation pathway. Separate experiments show that 5 and 6 undergo (Z) → (E) isomerization and photocyclization to imidazole 4. Quantum yields for these reactions show that the sequence 2 → 6 → 4 is a major pathway for the P4 phototransposition of 2 → 4. Isocyanides were also detected as intermediates in the P4 phototransposition of a variety of other pyrazoles confirming the generality of this pathway in pyrazole photochemistry. Direct irradiation of 1-methyl-5-phenylpyrazole (3) resulted in the formation of 1-methyl-5-phenylimidazole (7), 1-methyl-2-phenylimidazole (8), and 1-methyl-4-phenylimidazole (4). Deuterium labeling revealed that these products were formed by P4, P6, and P7 permutation pathways, respectively. (E)/(Z)-3-(N-methylamino)-3-phenylpropenenitrile (9) and (E)/(Z)-2-(N-methylamino)-2-phenylethenyl isocyanide (10) photocleavage products were also formed in this reaction. Irradiation of 3 in furan solvent did not result in phototransposition but led to the formation of endo and exo adducts formed by Diels-Alder reaction of furan with 4-phenyl-5-methyl-1,5-diazabicyclo[2.1.0]pent-2-ene. This constitutes the first direct evidence for the formation of a 1,5-diazabicyclo[2.1.0]hex-2-ene from photolysis of a pyrazole and is consistent with the electrocyclic ring closure - heteroatom migration mechanism suggested for the P6 and P7 phototranspositions.