We prove an explicit formula for a projection of singular vectors in the Verma module over a rank 2 Kac-Moody Lie algebra onto the universal enveloping algebra of the Heisenberg Lie algebra and of sl2. The formula is derived from a more general but less explicit formula due to Feigin, Fuchs, and Malikov [3]. In the simpler case of A1 the formula was… (More)