The reaction of n-glucosamine with lactic acid results in the formation of a glycoside linkage between the amino group of n-glucosamine and the hydroxyl group of lactic acid. This reaction is typically carried out in the presence of a Lewis acid catalyst, such as boron trifluoride etherate (BF3·OEt2). The reaction scheme is as follows:

$$n-Glucosamine + Lactic acid \xrightarrow{BF_3\cdot OEt_2} n-Glucosamine-6-O-lactate$$

The product, n-glucosamine-6-O-lactate, is a stable compound that can be isolated and purified. It is a white solid that is soluble in water and methanol. n-Glucosamine-6-O-lactate has a variety of applications in the pharmaceutical and food industries.