My husband and I are thinking of having a baby. We would like to have a baby boy. We know that TIMING and SEX POSITION are important. Is there other things we can do? Maybe a medicine to alkalize my vagina or reduce sperms with x chromosomes.

All the luck of the draw I'm afraid.
You get what you get.

Timing and position have no evidence in fact. IVF is the only sure way to direct gender selection, so far, although 'sperm sorting,' in use already by animal breeders, is being tried on humans.
The ethical problems are huge, of course. Look what happened in China. There are now so many boys that girls are being kidnapped to provide wives for boys in rural areas, even while girls are still being given up or aborted so that couples can have a son for their one allowed child.

Where did you get the idea that Timing and position have anything to do with it? As Joy said, the only way to control gender is if the egg is fertilized in vitro, then implanted.