It can be prepared in three different, but related ways: 1) The chloromethylation of 8-methoxycoumarin (I) with formaldehyde and HCl in refluxing acetic acid gives 5-chloromethyl-8-methoxycoumarin (II), which is reduced with H2 over Pd/C in DMF yielding 5-methyl-8-methoxycoumarin (III). The hydrolysis of (III) with refluxing 48% aqueous HBr affords 5-methyl-8-hydroxycoumarin (IV), which is condensed with epibromohydrin (A) by means of K2CO3 in refluxing butanone giving 5-methyl-8-(2,3-epoxypropoxy)coumarin (V). The epoxy ring of (V) is opened with HCl in butanone affording 5-methyl-8-(2-hydroxy-3-chloropropoxy)coumarin (VI) (1), which is finally condensed with tert-butylamine (B) in refluxing ethanol (1-3). 2) The cyclization of 5-methylguaiacol (VII) with malic acid (VIII) by means of H2SO4 at 100-5 C gives coumarin (III) already obtained (1). 3) The condensation of (IV) with epichlorohydrin (C) by means of piperidine at 100 C gives coumarin (VI) already obtained (1).

It can be prepared in three different, but related ways: 1) The chloromethylation of 8-methoxycoumarin (I) with formaldehyde and HCl in refluxing acetic acid gives 5-chloromethyl-8-methoxycoumarin (II), which is reduced with H2 over Pd/C in DMF yielding 5-methyl-8-methoxycoumarin (III). The hydrolysis of (III) with refluxing 48% aqueous HBr affords 5-methyl-8-hydroxycoumarin (IV), which is condensed with epibromohydrin (A) by means of K2CO3 in refluxing butanone giving 5-methyl-8-(2,3-epoxypropoxy)coumarin (V). The epoxy ring of (V) is opened with HCl in butanone affording 5-methyl-8-(2-hydroxy-3-chloropropoxy)coumarin (VI) (1), which is finally condensed with tert-butylamine (B) in refluxing ethanol (1-3). 2) The cyclization of 5-methylguaiacol (VII) with malic acid (VIII) by means of H2SO4 at 100-5 C gives coumarin (III) already obtained (1). 3) The condensation of (IV) with epichlorohydrin (C) by means of piperidine at 100 C gives coumarin (VI) already obtained (1).

It can be prepared in three different, but related ways: 1) The chloromethylation of 8-methoxycoumarin (I) with formaldehyde and HCl in refluxing acetic acid gives 5-chloromethyl-8-methoxycoumarin (II), which is reduced with H2 over Pd/C in DMF yielding 5-methyl-8-methoxycoumarin (III). The hydrolysis of (III) with refluxing 48% aqueous HBr affords 5-methyl-8-hydroxycoumarin (IV), which is condensed with epibromohydrin (A) by means of K2CO3 in refluxing butanone giving 5-methyl-8-(2,3-epoxypropoxy)coumarin (V). The epoxy ring of (V) is opened with HCl in butanone affording 5-methyl-8-(2-hydroxy-3-chloropropoxy)coumarin (VI) (1), which is finally condensed with tert-butylamine (B) in refluxing ethanol (1-3). 2) The cyclization of 5-methylguaiacol (VII) with malic acid (VIII) by means of H2SO4 at 100-5 C gives coumarin (III) already obtained (1). 3) The condensation of (IV) with epichlorohydrin (C) by means of piperidine at 100 C gives coumarin (VI) already obtained (1).

It can be prepared in three different, but related ways: 1) The chloromethylation of 8-methoxycoumarin (I) with formaldehyde and HCl in refluxing acetic acid gives 5-chloromethyl-8-methoxycoumarin (II), which is reduced with H2 over Pd/C in DMF yielding 5-methyl-8-methoxycoumarin (III). The hydrolysis of (III) with refluxing 48% aqueous HBr affords 5-methyl-8-hydroxycoumarin (IV), which is condensed with epibromohydrin (A) by means of K2CO3 in refluxing butanone giving 5-methyl-8-(2,3-epoxypropoxy)coumarin (V). The epoxy ring of (V) is opened with HCl in butanone affording 5-methyl-8-(2-hydroxy-3-chloropropoxy)coumarin (VI) (1), which is finally condensed with tert-butylamine (B) in refluxing ethanol (1-3). 2) The cyclization of 5-methylguaiacol (VII) with malic acid (VIII) by means of H2SO4 at 100-5 C gives coumarin (III) already obtained (1). 3) The condensation of (IV) with epichlorohydrin (C) by means of piperidine at 100 C gives coumarin (VI) already obtained (1).