Goldman Sachs partner Brooks Entwistle, who set up the Wall Street bank's India operations in 2006, will move to Singapore to be its Southeast Asia chairman and head of investment banking for that region, according to an internal memo obtained by Reuters.

Sonjoy Chatterjee, who joined the bank last year as a partner and India co-chief executive after 16 years with India's ICICI Bank , has been named chairman of Goldman Sachs for India, a second memo said.

Both memos were dated Friday.

Vijay Karnani, a company veteran who heads Goldman's securities business in India, will become co-CEO for India with Chatterjee, the second memo said.

Tim Leissner, a partner who has been co-president of Goldman Sachs in Singapore and head of investment banking for Southeast Asia, will move to Hong Kong to take up more senior coverage responsibilities across Asia, the first memo said.

Entwistle has been India country head since starting operations from a Mumbai hotel room after Goldman split from its local joint venture partner Kotak Mahindra Bank .

An American, Entwistle left the firm and later rejoined after serving as a district electoral supervisor with the United Nations Transitional Authority for Cambodia from 1992 to 1993.

He is among the longest-serving heads of a foreign investment bank in the fiercely competitive India market.

This week, Goldman said it will buy India's Benchmark Asset Management Co, which has about $700 million in assets under management.

(Reporting by Tony Munroe; Editing by Kim Coghill)