2-Methyl-3-tosyl-1,2,3,4-tetrahydroquinazoline

Two-dimensional proton–proton NMR correlation spectrum of 2-methyl-3-tosyl-1,2,3,4-tetrahydroquinazoline in acetone-d6. A colour code was used to highlight the observed H–H couplings.

Scheme 2 Pd-mediated hydrolysis of triethylamine in the presence of 2-tosylaminomethylaniline (HATs) to yield 2-methyl-3-tosyl-1,2,3,4-tetrahydroquinazoline and di(acetato)bis(diethylamine)palladium(II).

2-Methyl-3-tosyl-1,2,3,4-tetrahydroquinazoline

Yield = 12.3 mg (41%). 1H NMR (400 MHz, dmso-d6): δ/ppm 7.56 (d, J = 8.2 Hz, 2H, 2 × H-2′), 7.16 (d, J = 8.1 Hz, 2H, 2 × H-3′), 6.83 (m, 2H, H-5 + H-7), 6.46 (t, J = 7.1, 1H, H-6), 6.25 (d, J = 8.1 Hz, 1H, H-8), 6.09 (d, J = 3.4 Hz, 1H, NH), 5.22 (m, 1H, H-2), 4.54 (d, J = 17.2 Hz, 1H, CHH-4) and 4.36 (d, J = 17.2 Hz, 1H, CHH-4), 2.25 (s, 3H, CH3-4′) and 1.22 (d, 3H, J = 6.3 Hz, CH3-2). 1H NMR (250 MHz, CDCl3): δ/ppm 7.59 (d, J = 8.3 Hz, 2H, 2 × H-2′), 7.06 (d, J = 8.3 Hz, 2H, 2 × H-3′), 6.90 (t, 1H, H-7), 6.86 (d, 1H, H-5), 6.67 (dt, J = 7.5 and 1.1 Hz, 1H, H-6), 6.29 (d, J = 8.1 Hz, 1H, H-8), 5.36 (dq, J = 6.4 and 1.0 Hz, 1H, H-2), 4.70 (d, J = 17.4 Hz, 1H, CH2-4), 4.47 (d, J = 17.4 Hz, 1H, CH2-4), 2.29 (s, 3H, CH3) and 1.40 (d, J = 6.4 Hz, 3H, CH3). 13C NMR (62.5 MHz, CDCl3): δ/ppm 143.2 (C4′), 139.7 (C8a), 136.2 (C1′), 129.0 (2 × C3′), 127.6 (C5), 127.3 (2 × C2′), 126.4 (C7), 118.8 (C6), 116.9 (C4a), 116.4 (C8), 61.4 (CH), 41.8 (CH2), 21.5 (CH3) and 21.4 (CH3). IR (KBr, cm−1): 3387(s) ν(NH) cm−1, 1326(s) νas(SO2), 1158(vs) νs(SO2). MS (ESI) m/z = 325 (MNa+). HRMS calcd for C16H18N2NaO2S (MNa+): 325.0981; found, 325.0967. Elemental analysis (found): C 63.5, H 5.8, N 9.1; S, 10.5%. Calc. for C16H18N2O2S: C, 63.6; H, 6.0; N, 9.3; S, 10.6%.

http://pubs.rsc.org/en/content/articlehtml/2016/RA/C6RA20886J


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