2-{[5-(diphenylmethyl)-1,3,4-oxadiazol-2-yl]sulfanyl}-N-(pyrazin- 2-yl) acetamide

Molbank 2013, 2013(2), M800; doi:10.3390/M800

Short Note

2-{[5-(Diphenylmethyl)-1,3,4-oxadiazol-2-yl]sulfanyl}-N-(pyrazin-2-yl)acetamide

Prakash S. Nayak¹, Badiadka Narayana^1,* , Seranthimata Samshuddin¹ and Balladka Kunhanna Sarojini²

¹ Department of Studies in Chemistry, Mangalore University, Mangalagangotri-574 199, Karnataka, India² Research Department of Chemistry, P. A. College of Engineering, Nadupadavu, Mangalore 574153, Karnataka, India

nbadiadka@yahoo.co.uk.

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S-Alkylation of 5-(diphenylmethyl)-1,3,4-oxadiazole-2(3H)-thione (3) by 2-chloro-N-(pyrazin-2-yl)acetamide (2) affords the title compound, 2-{[5-(diphenylmethyl)-1,3,4-oxadiazol-2-yl]sulfanyl}-N-(pyrazin-2-yl)acetamide (4). The intermediate (2), in turn, was prepared by the acetylation of 2-aminopyrazine (1) with chloroacetyl chloride. The structure of the newly synthesized compound is characterized by IR, NMR and mass spectral data.

Melting point: 210–212 °C.
LCMS: m/z = 404.5 (M++1).

IR (KBr): νmax (cm−1), 3201 (N-H), 3041 (Ar-H), 1699 (alkyl-CO-NH) , 1555 (C=N, Ar C=C).
1H-NMR (400 MHz, DMSO-d6): δ ppm, 4.53 (s, 2H, S-CH2), 5.93 (s, 1H, Ph2-CH), 7.22–7.36 (m,
11H, Ar-H), 8.38–8.41 (m, 2H, Ar-H), 11.15 (s, 1H, NH).

13C-NMR (100 MHz, DMSO-d6,): δ ppm, 168.52 (C=O), 166.41, 163.89 (oxadiazole C’s), 148.75,
143.11, 140.54, 139.07, 136.55, 129.14, 128.75, 127.82 (aromatic C’s), 47.61(S-CH2), 36.78 (Ph2-CH).

Elemental analysis: Calculated for C21H17N5O2S, C, 62.52%; H, 4.25%; N, 17.36%; Found: C,
62.49%; H, 4.28%; N, 17.32%.

The formation of 2-{[5-(diphenylmethyl)-1,3,4-oxadiazol-2-yl]sulfanyl}-N-(pyrazin-2-yl)acetamide
(4) was confirmed by its NMR and mass spectral data. A singlet integrating for two protons at δ 4.53
in the 1H-NMR spectrum of compound (4) was due to -S-CH2 linkage. Another singlet observed at δ
5.93 ppm was due to the proton attached the carbon for which two phenyl groups were substituted. The signals of aromatic protons merged in the regions δ 7.22–7.36 ppm and 8.38–8.41 ppm as multiplets.NH proton appeared as a singlet at δ 11.15 ppm as a singlet. Mass spectrum showed a molecular ionpeak at m/z 404.5 (M++1) corresponding to the molecular formula of C21H17N5O2S. Elemental analysis and 13C-NMR spectrum also gave satisfactory results for the title compound.

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