Synthesis of 6' H-Spiro(indene-2,2'-[1,3]oxathiane)-1,3,5'-triones. -Spiro compounds (III) and (VII) are prepared from ninhydrin (I). -(UKHIN, L. Y.; BELOUSOVA*, L. V.; SHEPELENKO, E. N.; MORKOVNIK, A. S.; Mendeleev Commun. 23 (2013) 6, 352-353, http://dx.