India’s “dosa king”, the founder of a global restaurant chain, has died days after losing a last-ditch attempt to avoid a life sentence for murder.

P Rajagopal, 71, who rose from humble beginnings to run one of the world’s largest chains of vegetarian restaurants, had been convicted of killing the husband of a woman he wanted to make his third wife.

He reportedly became obsessed with the woman, then in her 20s, who was already married and had rejected his advances. He harassed, threatened and tried to blackmail her, and hired a gunman to kill the woman’s husband. One attempt was unsuccessful, but the man’s body was later found in a forest in Tamil Nadu.

Rajagopal had fought for 15 years to avoid prison but was ordered to surrender last week. He gave himself up at the high court in Chennai, arriving in an ambulance with an oxygen mask strapped to his face.

Vehicles pass a branch of Saravana Bhavan in Chennai. The vegetarian restaurant chain was founded in 1981. Photograph: Arun Sankar/AFP/Getty

On Tuesday, he was taken with heart problems to Vijaya hospital in Chennai, where he died. “We failed to revive him and he passed away this morning due to cardiac failure,” a hospital official told Agence France-Presse.

His restaurant chain, Saravana Bhavan, serves south Indian delicacies such as dosa pancakes, deep-fried vadas and idli rice cakes. Inside some branches, copies of his memoirs are also sold.

“I moved to Chennai maybe about 25 or 26 years ago and Saravana Bhavan was an iconic place,” said Ameeta Agnihotri, a food critic in Chennai. “It was the place that we went to for hygienic, reasonably priced food.”

Born in a remote village in Tamil Nadu, Rajagopal started out as a grocer, before opening his debut restaurant in the KK Nagar township in 1981. Today his chain has scores of branches across India as well as more than 80 countries, with restaurants in London, Sydney and New York popular among the diaspora.

The chain employs thousands, and in Chennai staff are reported to receive generous pensions and benefits, inspiring fierce loyalty.

In 2004, Rajagopal was found guilty and sentenced to 10 years. When he appealed, the sentence was increased to life and the punishment was upheld by the supreme court in March.