Silica-supported Preyssler nano particles: a green, reusable and highly efficient heterogeneous catalyst for the synthesis of carbamatoalkyl naphthols

Figures & data

short-legendScheme 1. 

Table 1. Synthesis of methyl [(2-hydroxynaphthalen-1-yl)(phenyl)methyl] carbamate 4a in the presence of Silica-supported Preyssler nano particles at different temperatures in solvent-free conditions.

Entry	Temperature (°C)	Time (min)	Yield (%)^a
1	25	30	20
2	50	20	35
3	70	8	54
4	90	3	84
5	120	3	87
^aIsolated yields.

Table 2. Silica-supported Preyssler nano particles catalyzed synthesis of carbamatoalkyl naphthols.

				M.P. (°C)
Entry	Products^a	Time (min)	Yield (%)^b	Found	Reported
1		3	84	222–224	217–218
2		2	87	201–203	196–198
3		2	88	203–205	198–200
4		3	83	194–196	192 (dec)
5		3	82	230–232	–
6		3	86	241–242	–
7		2	90	253–255	252 (dec)
8		2	91	200–202	205–207
9		20	–	–	–
10		20	–	–	–
^aNew products (4e and 4f) were characterized by IR, ^1H NMR, ^13C NMR and MASS spectra and known products were characterized by IR and ^1H NMR and comparison of their melting points with those of authentic samples 34.
^bIsolated yields.

Table 3. The comparison of efficiency of Preyssler nano particles in the synthesis of carbamatoalkyl naphthols after three times.

		Yield%^a/run
Entry	Ar	First	Second	Third
4a	C6H5	84	82	79
4c	4-ClC6H4	88	85	84
4h	4-O2NC6H4	91	87	85
^aIsolated yields.

Shaterian , H.R. ; Hosseinian , A. ; Ghashang , M. Tetrahedron Lett . 2008 , 49 , 5804 5806 .

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