TBAF-Catalyzed Synthesis of 5-Substituted 1H-Tetrazoles Under Solventless Conditions

Transcription

1 Supporting Information TBAF-Catalyzed Synthesis of -Substituted H-Tetrazoles Under Solventless Conditions David Amantini,* Romina Beleggia, Francesco Fringuelli, Ferdinando Pizzo,* Luigi Vaccaro Dipartimento di Chimica, Università d i Perugia via Elce di Sotto 8, I-06 Perugia Italy pizzo@unipg.it COTETS Experimental Section References S S7 S

2 Experimental Section MR spectra were recorded at 00 or 00 MHz for proton and at 00.6 or 0. MHz for carbon nuclei in CD SOCD and residual internal peak at.0 ppm was used as standard. The products were purified by recristallization or by column chromatography carried out on silica gel (0-00 mesh), and by using ethylacetate/methanol/acetic acid mixtures as eluent. lting points are uncorrected. itriles a-k, TMS and TBAF H O were purchased and used without further purification, - substituted H-tetrazoles a, b, e, c, f, g, h, i, k, 6 and j 7 are known compounds while d is a new compound. -Phenyltetrazole (a) : a In a screw capped vial equipped with a magnetic stirrer, TBAF H O (0. g,.0 mmol), benzonitrile (a) (0.06 g,.0 mmol) and TMS (0. g,.0 mmol) were added and the resulting mixture heated under vigorous stirring at 8 C for 8 h. The crude reaction mixture was transferred into a separatory funnel with 0 ml of ethylacetate and TBAF was removed by washing the organic phase with a M HCl aqueous solution ( x ml). The organic layer was dried (a SO ) and concentrated under reduced pressure to furnish pure -phenyl--h-tetrazole (a) as a white solid in 86% yield (0. g). White solid, mp = -6 C, (ethylacetate). H MR (00 MHz, CD SOCD ) δ: (m, H), (m, H); C MR (00.6 MHz, CD SOCD ) δ:., 7.0, 9.,.,.. Anal. Calcd for C 7 H 6 : C, 7.; H,.;, 8.. Found C, 7.; H,.;, 8.. -( -nitrophenyl) tetrazole (b) : O b S

3 In a screw capped vial equipped with a magnetic stirrer, TBAF H O (0. g,.0 mmol), p- nitrobenzonitrile (b) (0.96 g,.0 mmol) and TMS (0. g,.0 mmol) were added and the resulting mixture heated under vigorous stirring at 8 C for h. The crude reaction mixture was transferred into a separatory funnel with 0 ml of ethylacetate and TBAF was removed by washing the organic phase with a M HCl aqueous solution ( x ml). The organic layer was dried (a SO ) and concentrated under reduced pressure to furnish pure -( -nitrophenyl) tetrazole (b) as a yellow solid in 9% yield (0.6 g). Yellow solid, mp = 9- C, (ethylacetate). H MR (00 MHz, CD SOCD ) δ: 8.0 (bd, J = 8. Hz, H), 8. (bd, J = 8. Hz, H); C MR (0. MHz, CD SOCD ) δ:., 8., 0.7, 8.6,.. Anal. Calcd for C 7 H O : C,.98; H,.6;, 6.6. Found C,.9; H,.6;, ( -methoxyphenyl) tetrazole (c) : O c In a screw capped vial equipped with a magnetic stirrer, TBAF H O (0. g,.0 mmol), m- methoxybenzonitrile (c) (0.66 g,.0 mmol) and TMS (0. g,.0 mmol) were added and the resulting mixture heated under vigorous stirring at 8 C for 6 h. The crude reaction mixture was transferred into a separatory funnel with 0 ml of ethylacetate and TBAF was removed by washing the organic phase with a M HCl aqueous solution ( x ml). The organic layer was dried (a SO ) and concentrated under reduced pressure to furnish pure -( -methoxyphenyl) tetrazole (c) as a yellow solid in 88% yield (0.0 g). White solid, mp = 6-7 C, (ethylacetate). H MR (00 MHz, CD SOCD ) δ:.8 (s, H), 7.6 (bdd, J =.6, 8. Hz, H), 7. (t, J = 8. Hz, H), (m, H); C MR (00.6 MHz, CD SOCD ) δ:.,., 7., 9.,., 0.7,., 9.8. Anal. Calcd for C 8 H 8 O: C,.; H,.8;,.80. Found C,.6; H,.;,.7. -( -acetylphenyl) tetrazole (d): O d S

4 In a screw capped vial equipped with a magnetic stirrer, TBAF H O (0. g,.0 mmol), p- acetylbenzonitrile (d) (0.90 g,.0 mmol) and TMS (0. g,.0 mmol) were added and the resulting mixture heated under vigorous stirring at 8 C for 7 h. The crude reaction mixture was transferred into a separatory funnel with 0 ml of ethylacetate and TBAF was removed by washing the organic phase with a M HCl aqueous solution ( x ml). The organic layer was dried (a SO ) and concentrated under reduced pressure to furnish pure -( -acetylphenyl) tetrazole (d) as a white solid in 9% yield (0. g). White solid, mp = 7-7 C, (ethylacetate-methanol). H MR (00 MHz, CD SOCD ) δ:.6 (s, H), (m, H); C MR (0. MHz, CD SOCD ) δ: 7., 7., 9., 9., 8.6,.9, Anal. Calcd for C 9 H 8 O: C, 7.; H,.8;, Found C, 7.; H,.;, ( -methyl-, -biphenyl- -yl)-tetrazole (e) : e ' ' ' ' ' ' In a vial equipped with a magnetic stirrer, TBAF H O (0. g,.0 mmol), biphenylnitrile e (0.86 g,.0 mmol) and TMS (0.6 g,.0 mmol) were added. The vial was sealed by flame and heated under vigorous stirring at 0 C for 6 h. The crude reaction mixture was transferred into a separatory funnel with 0 ml of ethylacetate and TBAF was removed by washing the organic phase with a M HCl aqueous solution ( x ml). The organic layer was dried (a SO ) and concentrated under reduced pressure to furnish pure -( -methyl-, -biphenyl- -yl)-tetrazole (e) as a light yellow solid in 97% yield (0.8 g). Light yellow solid, mp = 9-0 C, (ethylacetate). H MR (00 MHz, CD SOCD ) δ:.8 (s, H), 6.98 (bd, J = 7.9 Hz, H), 7. (bd, J = 7.9 Hz, H), 7. (bt, J = 6.8 Hz, H), (m, H); C MR (0. MHz, CD SOCD ) δ:.,., 7.9, 9., 9.,.0,.0,., 6.7, 7.,.9,.. Anal. Calcd for C H : C, 7.7; H,.;,.7. Found C, 7.; H,.;,.6. -(tetrazol- -yl)pyridine (f) : 6 f S

5 In a screw capped vial equipped with a magnetic stirrer, TBAF H O (0. g,.0 mmol), nicotinonitrile (f) (0.08 g,.0 mmol) and TMS (0. g,.0 mmol) were added and the resulting mixture heated under vigorous stirring at 0 C for 9 h. The crude reaction mixture was transferred into a 0 ml round bottom flask and the product recrystallized from water to furnish pure -(tetrazol- -yl)pyridine (f) as a white solid in 8% yield (0.0 g). White solid, mp = 9-0 C, (water). H MR (00 MHz, CD SOCD ) δ: (m, H), (m, H), (m, H), 9. (s, H); C MR (00.6 MHz, CD SOCD ) δ:.0,.,.6, 7.6,.8,.. Anal. Calcd for C 6 H : C, 8.98; H,.;, Found C, 8.9; H,.;, ( -furyl)tetrazole (g) : O H g In a screw capped vial equipped with a magnetic stirrer, TBAF H O (0. g,.0 mmol), - furonitrile (g) (0.86 g,.0 mmol) and TMS (0. g,.0 mmol) were added and the resulting mixture heated under vigorous stirring at 8 C for h. The crude reaction mixture was transferred into a separatory funnel with 0 ml of ethylacetate and TBAF was removed by washing the organic phase with a M HCl aqueous solution ( x ml). The organic layer was dried (a SO ) and concentrated under reduced pressure to furnish pure -( -furyl)tetrazole (g) as a light yellow solid in 9% yield (0.9 g). Light yellow solid, mp = 0-0 C, (ethylacetate). H MR (00 MHz, CD SOCD ) δ: (m, H), 7.7 (bd, J =. Hz, H), (m, H); C MR (0. MHz, CD SOCD ) δ:.6,., 0., 6., 8.. Anal. Calcd for C H O: C,.; H,.96;,.6. Found C,.; H,.9;,.09. -(tetrazol- -yl)-h-indole (h) : 7 7a H 6 H a h In a vial equipped with a magnetic stirrer, TBAF H O (0. g,.0 mmol), -cyanoindole (h) (0.8 g,.0 mmol) and TMS (0. g,.0 mmol) were added. The vial was sealed by flame and heated under vigorous stirring at 0 C for 8 h. The crude reaction mixture was transferred into a S

6 separatory funnel with 0 ml of ethylacetate and TBAF was removed by washing the organic phase with a M HCl aqueous solution ( x ml). The organic layer was dried (a SO ) and concentrated under reduced pressure to furnish pure -(tetrazol- -yl)-h-indole (h) as a white solid in 8% yield (0.0 g). White solid, mp = 6-7 C, (methanol). H MR (00 MHz, CD SOCD ) δ: (m, H), 7.9 (bt, J =.9 Hz, H), 7.9 (d, J = 8. Hz, H), 7.78 (dd, J =.6, 8. Hz, H), 8.8 (bs, H),.8 (bs, H); C MR (0. MHz, CD SOCD ) δ: 0.,.6,.8, 9.8, 0., 7., 8.0, 7., 6.. Anal. Calcd for C 9 H 7 : C, 8.7; H,.8;, 7.8. Found C, 8.; H,.79;, Benzyltetrazole (i) 6 : i H In a vial equipped with a magnetic stirrer, TBAF H O (0. g,.0 mmol), phenylacetonitrile (i) (0. g,.0 mmol) and TMS (0. g,.0 mmol) were added. The vial was sealed by flame and heated under vigorous stirring at 0 C for h. The crude reaction mixture was transferred into a separatory funnel with 0 ml of ethylacetate and TBAF was removed by washing the organic phase with a M HCl aqueous solution ( x ml). The organic layer was dried (a SO ) and concentrated under reduced pressure to furnish pure -Benzyltetrazole (i) as a white solid in 9% yield (0.98 g). White solid, mp = - C, (ethylacetate). H MR (00 MHz, CD SOCD ) δ:.8 (s, H), (m, H), (m, H); C MR (00.6 MHz, CD SOCD ) δ: 9., 7., 8.8, 8.8, 6.,.. Anal. Calcd for C 8 H 8 : C, 9.99; H,.0;,.98. Found C, 9.8; H,.0;,. -Butyltetrazole (j) 7 : H j In a vial equipped with a magnetic stirrer, TBAF H O (0. g,.0 mmol), valeronitrile (j) (0.66 g,.0 mmol) and TMS (0. g,.0 mmol) were added. The vial was sealed by flame and heated under vigorous stirring at 0 C for h. The crude reaction mixture was charged in a column and chromatographed to furnish pure -Butyltetrazole (i) as a white solid in 80% yield (0.0 g). White solid, mp = - C, (ethylacetate). H MR (00 MHz, CD SOCD ) δ: 0.89 (s, H),.9 (sextet, J = 7. Hz, H),.67 (p, J = 7. Hz, H),.86 (t, J = 7.6 Hz, H); C MR (00.6 MHz, CD SOCD ) S6

7 δ:.,.,., 9., 6.0. Anal. Calcd for C H 0 : C, 7.60; H, 7.99;,.. Found C, 7.7; H, 7.97;,.9 -t-butyltetrazole (k) 6 : k H In a vial equipped with a magnetic stirrer, TBAF H O (0. g,.0 mmol), pivalonitrile (k) (0.66 g,.0 mmol) and TMS (0. g,.0 mmol) were added. The vial was sealed by flame and heated under vigorous stirring at 0 C for 8 h. The crude reaction mixture was charged in a column and chromatographed to furnish pure -t-butyltetrazole (k) as a slightly yellow oil in 8% yield (0.06 g). H MR (00 MHz, CD SOCD ) δ:. (s, 9H); C MR (00.6 MHz, CD SOCD ) δ: 9., 0., 6.9. Anal. Calcd for C H 0 : C, 7.60; H, 7.99;,.. Found C, 7.; H,8.0;,.. References ) Demko, Z. P.; Sharpless, K. B. J. Org. Chem. 00, 66, ) Rees, C. W.; Sivadasan, S.; White, A. J. P.; Williams, D. J. J. Chem. Soc., Perkin Trans. 00,, -. ) Alterman, M.; Hallberg, A. J. Org. Chem. 000, 6, ) Shie, J.-J.; Fang, J.-M. J. Org. Chem. 00, 68, ) Wentrup, C.; Becker, J. J. Am. Chem. Soc. 98, 06, ) Curran, D. P.; Hadida, S.; Kim, S.-Y. Tetrahedron 999,, ) Wittenberger, S. J.; Donner, B. G. J. Org. Chem. 99, 8, 9-. S7