Photolysis of 1,2-naphthoquinone-1-methide dimers

Naphthoquinonemethide dimers I $(R=H, Br, CMe_3)$ on photolysis isomerized to the phenolic phenalene derivatives II (same $R; R_1=H)$ via a $\beta-C-O$ cleavage. Methylation and acetylation of II $(R=CMe_3, R_1=H)$ gave II $(R=CMe_3; R_1=Me, Ac)$

One pot synthesis of polycyclic oxygen aromatics. Part III mechanism of formation

Reaction of 6-Image -butyl-1-bromomethyl-2-(2-tetrahydropyranyloxy)-naphthalene2c with tetrachlorocatechol (TCC) in acetone in presence of K2CO3 gave diastereomers 6c and 7c. A mechanism (Scheme-1) invoking the base induced cleavage of the pyranyl ether 2 to 1,2-naphthoquinone-1-methide 8 as the first step has been postulated. The cleavage of the pyranyl ether linkage in 2 to give dimers 4 and 5 of 1,2-naphthoquinone-1-methide has been demonstrated with different bases. 1,2-Naphthoquinone-1-methide 8, thus generated, undergoes Michael addition with TCC followed by elimination of chloride ions to give a diketone, which further undergoes aldolisation with acetone to give diastereomers 6 and 7. Michael reaction of 8, generated Image from pyranyl ethers 2a-c, with tetrabromocatechol (TBC) under similar-reaction conditions gave the expected monobromo compounds 6h, 6i, 6k, 7n, 7n and 7q. The last step in the proposed mechanism, Image ., aldolisation has also been demonstrated using different ketonic solvents. Thus, reaction of 2a-c with TCC/TBC in diethyl ketone/methyl ethyl ketone under similar reaction conditions gave the expected compounds 6 and 7

One pot synthesis of polycyclic oxygen aromatics. Part III Mechanism of formation

Reaction of 6-tert -butyl-1-bromomethyl-2-(2-tetrahydropyranyloxy)-naphthalene 2c with tetrachlorocatechol (TCC) in acetone in presence of K2CO3 gave diastereomers 6c and 7c. A mechanism (Scheme-1) invoking the base induced cleavage of the pyranyl ether 2 to 1,2-naphthoquinone-1-methide 8 as the first step has been postulated. The cleavage of the pyranyl ether linkage in 2 to give dimers 4 and 5 of 1,2-naphthoquinone-1-methide has been demonstrated with different bases. 1,2-Naphthoquinone-1-methide 8, thus generated, undergoes Michael addition with TCC followed by elimination of chloride ions to give a diketone, which further undergoes aldolisation with acetone to give diastereomers 6 and 7. Michael reaction of 8, generated in situ from pyranyl ethers 2a-c, with tetrabromocatechol (TBC) under similar-reaction conditions gave the expected monobromo compounds 6h, 6i, 6k, 7n, 7n and 7q. The last step in the proposed mechanism, viz., aldolisation has also been demonstrated using different ketonic solvents. Thus, reaction of 2a-c with TCC/TBC in diethyl ketone/methyl ethyl ketone under similar reaction conditions gave the expected compounds 6 and 7

One pot synthesis of polycyclic oxygen aromatics

Reaction of 1-bromomethyl-2-(2-tetrahydropyranyloxy) naphthalene (5a) with tetrachlorocatechol in acetone in presence of anhydrous potassium carbonate resulted in the formation of compounds 7a 8a and 9a along with diastereomeric products to which $\pm\hspace{1mm} cis$ and $trans$-8-chloro-10-hydroxy-10-(2-oxopropyl) spiro [11$H$-benzo$[a]$xanthen-ll2'(1'$H$ naphtho [21-$b$ furan]-9 (1O$H$-one (13a and l4a) structures were assigned based on spectral data. Similar reaction of the corresponding bromo compound (5b) using acetone or diethyl ketone as solvent gave the corresponding diastereomeric pair of compounds (13 and 14). X-ray crystal structure analysis of one of the $trans$ compounds 14c further confirmed the assigned structur

One pot synthesis of polycyclic oxygen aromatics

Reaction of 1-bromomethyl-2-(2-tetrahydropyranyloxy) naphthalene (5a) with tetrachlorocatechol in acetone in presence of anhydrous potassium carbonate resulted in the formation of compounds 7a 8a and 9a along with diastereomeric products to which ±cis - trans and -8-chloro-10-hydroxy-10-(2-oxopropyl) spiro [11 H̲ -benzo[a̲] xanthen-ll2'(1'H̲) naphtho [21-b̲ furan]-9 (1O H̲ -one (13a and l4a) structures were assigned based on spectral data. Similar reaction of the corresponding bromo compound (5b) using acetone or diethyl ketone as solvent gave the corresponding diastereomeric pair of compounds (13 and 14). X-ray crystal structure analysis of one of the trans compounds 14c further confirmed the assigned structure

Reaction of tetrahydropyranyl ether of 1-bromomethyl-2-naphthol with tetrachlorocatechol-structures of novel products

Structures of novel products obtained in the reaction of the title naphthol ether $I (R = H, Br)$ with tetrachlorocatechol in the presence of anhyd. $K_2CO_3$ in $Me_2CO$ have been assigned as $II (R1, R2 = CH_2COMe, OH; R1 \neq R2)$ on the basis of spectral data. Structure of $II (R = Br; R1 = MeCOCH_2; R2 = OH)$ has been confirmed by x-ray crystal structure analysis