A. R. Modarresi-Alam et al. / Tetrahedron 63 (2007) 8723–8726
8725
ꢀ
37
4
. Experimental
Menthyl carbamate 1a: mp¼166–168 C and lit., 156–
ꢀ
ꢀ
38
1
57 C. Ethyl carbamate 1b: mp¼46–48 C and lit., 48–
ꢀ
ꢀ
38
4
.1. General
50 C. 1-Propyl carbamate 1c: mp¼58–59 C and lit.,
ꢀ
ꢀ
38
6
0 C. 1-Butyl carbamate 1e: mp¼53–55 C and lit.,
1
13
ꢀ
ꢀ
H NMR and C NMR spectra were recorded by Bruker
Avance DRX500 (500 MHz). The IR spectra were obtained
on a Shimadzu-470. Melting points were recorded by Elec-
trothermal 9100 and were uncorrected. Thin layer chromato-
graphy (TLC) was carried out using plastic sheets precoated
with silica gel 60 F. All starting materials such as alcohols,
phenols, NaOCN, and solvents were purchased from Fluka,
Merck, and Aldrich chemical companies and were purified
with the proper purification techniques before use. The
products 1 were identified through comparison of their spec-
tral data, IR, H NMR, C NMR, TLC, and physical prop-
erties with those of authentic samples.
was prepared from silica gel and perchloric acid according
54 C. Cyclohexyl carbamate 1e: mp¼108–110 C and
2
2
ꢀ
108 C and lit., 107–108 C. Benzyl carbamate 1g:
lit., 108–110 C. tert-Butyl carbamate 1f: mp¼106–
ꢀ
15
ꢀ
ꢀ
38
ꢀ
mp¼87–89 C and lit., 91 C. Ethylene glycol monoiso-
ꢀ
39
propyl ether carbamate 1h: mp¼57–59 C and lit.,
ꢀ
ꢀ
ꢀ
22
53 C. Allyl carbamate 1i: mp¼19–21 C and lit., 19–
ꢀ
15
21 C. Phenyl carbamate 1j: mp¼141–143 C and lit.,
ꢀ
136 C and lit., 134–136 C. 4-Bromophenyl carbamate
145–148 C. 4-Methylphenyl carbamate 1k: mp¼134–
3
5,36
ꢀ
22
ꢀ
22
ꢀ
ꢀ
1l: mp¼139–142 C and lit., 139–142 C. 2-tert-Butyl-4-
1
13
ꢀ
22
methylphenyl carbamate 1m: mp¼143–144 C and lit.,
2
2,30,31
ꢀ
180 C and lit., 175–177 C. Naphthalen-2-yl carbamate
HClO –SiO
143–144 C. Naphthalen-1-yl carbamate 1n: mp¼178–
4
2
ꢀ
30
ꢀ
2
8
ꢀ
31
ꢀ
to the literature.
.2. General procedure
In a typical procedure, to a mixture of sodium cyanate
1o: mp¼157–158 C and lit., 156–157 C.
4
Acknowledgements
(
(
2 mmol) and HClO –SiO (2 g, 1 mmol), alcohol or phenol
4
1.0 mmol) was added and the mixture was pulverized in
ꢀ
The Sistan and Baluchestan University Graduate Council
supported this research.
2
a mortar at room temperature or 55–65 C for appropriate
time (Table 1). The reaction was monitored in TLC. After
completion of the reaction, CHCl was added and the mix-
References and notes
3
ture was filtered for separation of the reagent. The solvent
(CHCl ) was evaporated to give the product. Pure products
were obtained in high yields, as summarized in Table 1.
1. Dibenedetto, A.; Aresta, M.; Fragale, C.; Narracci, M. Green
Chem. 2002, 4, 439–443 and references therein.
3
2
. Gupte, S. P.; Shivarkar, A. B.; Chaudhari, R. V. Chem.
Commun. 2001, 2620–2621.
In cases of a- and b-naphthol (entries 14 and 15) after re-
moving CHCl , petroleum ether and then ethyl acetate
were added. The obtained solid was pure a- or b-naphthyl
carbamate 1n and 1o.
3. Feldman, D.; Barbalata, A. Synthetic Polymers, Technology,
Properties, Applications; Chapman and Hall: London, 1996;
p 273.
3
4
. Mindl, J.; Hrab ꢀı k, O.; St eˇ rba, V.; Kav ꢀa lek, J. Collect. Czech.
Chem. Commun. 2000, 65, 1262–1272.
5. Pesticide Chemistry; Motolcsy, G., Nadasy, M., Andriska, V.,
Eds.; Academiai Kiado: Budapest, 1988; p 90.
6. Thompson, A. Pesticide Outlook 2002, 13, 84–86.
7. Martin, L. L.; Davis, L.; Klein, J. T.; Nemoto, P.; Olsen,
G. E.; Bores, G. M.; Camacho, F.; Petko, W. W.; Rush,
D. K.; Selk, D.; Smith, C. P.; Vargas, H. M.; Wilson, J. T.;
Effland, R. C.; Fink, D. M. Bioorg. Med. Chem. Lett. 1997,
7, 157–162.
8. Greene, W. T.; Wuts, P. G. M. Protective Groups in Organic
Synthesis, 2nd ed.; Wiley: New York, NY, 1991; p 327 and
p 403.
Naphthalen-1-yl carbamate 1n: reaction afforded white
ꢀ
30
crystals 1n, 72% yield, mp¼178–180 C. IR (KBr,
ꢁ
1
cm ): 3430 (m), 3343 (vw), 3275 (w), 3200 (w), 3055
vw), 2920 (vw), 1698 (vs), 1603 (s), 1360 (vs), 1254 (s),
222 (s), 1150 (m), 1082 (s), 1041 (m), 1010 (m), 958
(
1
1
(
m), 801 (s), 773 (vs), 582 (m), 553 (w). H NMR
500 MHz, CDCl ) d (ppm): 6.10 (br d, 2H), 7.20 (d,
(
3
J¼7.5 Hz, 1H), 7.35–7.45 (m, 3H), 7.63 (d, J¼8.2 Hz,
1
2
1
1
4
H), 7.78 (dd, J¼9.3, 2.1 Hz, 1H), 7.92 (dd, J¼8.8,
1
3
.1 Hz, 1H). C NMR (125 MHz, CDCl ) d (ppm): 117.7,
3
20.8, 124.8, 124.9, 125.6, 125.7, 126.9, 127.3, 134.0,
46.2, 154.7. Anal. Calcd for C H NO : C, 70.59; H,
.81; N, 7.49. Found: C, 70.80; H, 4.71; N, 7.60%.
1
1
9
2
9. Yoshida, M.; Hara, N.; Okuyama, S. Chem. Commun. 2000,
1
51–152 and references therein.
10. Ichikawa, Y.; Osada, M.; Ohtani, I. I.; Isobe, M. J. Chem. Soc.,
Perkin Trans. 1 1997, 1449–1455.
Naphthalen-2-yl carbamate 1o: reaction afforded white crys-
ꢀ
31
ꢁ1
tals 1o, 82% yield, mp¼157–158 C. IR (KBr, cm ):
3
1
405 (m), 3038 (w), 3270 (w), 3197 (vw), 3055 (vw),
697 (vs), 1610 (w), 1506 (w), 1388 (s), 1355 (s), 1239
11. Kocovsky, P. Tetrahedron Lett. 1986, 27, 5521–5524.
12. Raucher, S.; Jones, D. S. Synth. Commun. 1985, 15, 1025.
13. Graf, R. Chem. Ber. 1963, 96, 56–67.
14. Fuks, R.; Hartemink, M. A. Bull. Chim. Belg. 1973, 82, 23.
15. Loev, B.; Kormendy, M. F. J. Org. Chem. 1963, 28, 3421–
3426.
16. Tanaka, K. Solvent-Free Organic Synthesis; Wiley-VCH:
Weinheim, 2003.
17. Nagendrappa, G. Resonance 2002, 7, 64–77.
18. Varma, R. S. Green Chem. 1999, 1, 43–55.
19. Varma, R. S. Tetrahedron 2002, 58, 1235–1255.
(
(
s), 1206 (s), 1155 (m), 987 (s), 895 (m), 858 (m), 821
m), 775 (m), 758 (w), 734 (m), 543 (w), 474 (m). H
1
NMR (500 MHz, CDCl ) d (ppm): 6.25 (br s, 2H), 7.20
3
(
dd, J¼8.7, 2.1 Hz, 1H), 7.34–7.41 (m, 2H), 7.49 (d,
J¼2.1 Hz, 1H), 7.71 (d, J¼8.0 Hz, 1H), 7.75 (d, J¼8.7 Hz,
1
3
2
1
1
7
H). C NMR (125 MHz, CDCl ) d (ppm): 117.9, 121.2,
3
24.8, 125.8, 126.9, 127.1, 128.5, 130.5, 133.1, 148.3,
54.9. Anal. Calcd for C H NO : C, 70.59; H, 4.81; N,
.49. Found; C, 71.20; H, 4.65; N, 7.54%.
1
1
9
2