Certain pyrano-furo-azuleno-pyridines

#In accordance with this invention it has been discovered that compounds of the tautomeric formulae ##STR1## wherein R.sub.1 and R.sub.2 are individually hydrogen or taken together form ##STR2## R.sub.3 is hydrogen or ##STR3## R.sub.4 and R.sub.5 are lower alkyl or form a cycloalkyl; and R.sub.6, R.sub.7 and R.sub.8 are hydrogen, halogen or nitro are useful as coloring agents for foodstuff, vitamin, pharmaceutical and cosmetic compositions.

#In accordance with another embodiment of the invention, compounds of the formulae ##STR4## and ##STR5## wherein R.sub.3, R.sub.4 and R.sub.5 are as above; and R is ##STR6## lower alkyl or ##STR7## R.sub.6, R.sub.7 and R.sub.8 are as above; with the proviso that when R is ##STR8## R.sub.3 is other than hydrogen are useful as coloring agents for foodstuffs, pharmaceuticals, vitamins and cosmetic compositions.

#In accordance with another embodiment of this invention, there is provided a coloring agent (coloring agent III) produced by cultivating a strain of Streptomyces Sp X-14077. This coloring agent is an amorphous red solid. While its exact structural formula is not known, it has a 1-propyl-3-methyl-azuleno[2,3-c]pyridine dione chromophore and its isopropylidene derivative has an empirical formula C.sub.26 H.sub.27 NO.sub.8.

#The composition of the media used for cultivation and description of growth characteristics of this organism is given as follows:

#Medium 1 ("Fermentation medium")

#Bacto Thermoactinomyces fermentation broth (Difco) to which 1.5% of agar was added.