Why has the little nation of Qatar spent 3 billion dollars to support the rebels in Syria?
Could it be because Qatar is the largest exporter of liquid natural gas in the world and Assad won't let them build a natural gas pipeline through Syria? Of course. Qatar wants to install a puppet regime in Syria that will allow them to build a pipeline which will enable them to sell lots and lots of natural gas to Europe. Why is Saudi Arabia spending huge amounts of money to help the rebels and why has Saudi Prince Bandar bin Sultan been "jetting from covert command centers near the Syrian front lines to the Élysée Palace in Paris and the Kremlin in Moscow, seeking to undermine the Assad regime"? Well, it turns out that Saudi Arabia intends to install their own puppet government in Syria which will allow the Saudis to control the flow of energy through the region. On the other side, Russia very much prefers the Assad regime for a whole bunch of reasons. One of those reasons is that Assad is helping to block the flow of natural gas out of the Persian Gulf into Europe, thus ensuring higher profits for Gazprom. Now the United States is getting directly involved in the conflict. If the U.S. is successful in getting rid of the Assad regime, it will be good for either the Saudis or Qatar (and possibly for both), and it will be really bad for Russia. This is a strategic geopolitical conflict about natural resources, religion and money, and it really has nothing to do with chemical weapons at all.
This is from "Is The United States Going To Go To War With Syria Over A Natural Gas Pipeline?" It's on the Alex Jones' Infowars website. Normally, I'm not a fan of that site but this article is pretty factual. Moreover, an economist friend who regularly deals with military people in the Middle East told me months ago, after returning from a trip to Jordan, that a huge part of the support of various outsiders in the conflict is over the protagonists' position on the pipeline.
I don't vouch for the last line in the quote above, and nothing in what leads up to the last line suggests that chemical weapons are irrelevant. But it is pretty clear that Putin does not want the new competition in Europe that a pipeline across Syria would create. It seems, therefore, that preventing the pipeline is one of Putin's main motives in supporting Syria's Assad.